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need RAM recommendation - please help
"Paul" wrote in message ... glee wrote: "Paul" wrote in message ... Adam wrote: Need RAM recommendation for the following motherboard ... - ASUS M5A99X Evo - AM3+ - 990X - SATA 6Gbps and USB 3.0 - ATX DDR3 2133 Motherboards I am thinking about the following ... - Crucial Ballistix 240-Pin DDR3 but need help with the specific model and amount (at least 8 GB due to VirtualBox/VM usage). Check the customer reviews on Newegg, for each product you are interested in. Some RAM has a high enough failure rate, you should stay away from it. The customer reviews, tells you what to avoid. Well I wouldn't go solely by some customer reviews. RAM by all the major suppliers (Crucial, Corsair, etc) is all good. Better to use RAM from the approved list suggested by the board maker Asus. This is categorically not true. Some major manufacturers, have had *major* problems with reliability. To the point they even switched chip supplier, when making the DIMMs to try to stop it. And this is why we read customer reviews, to easily gather (data mine) the knowledge that is available. If there is an obvious problem, and a lot of unhappy customers, the customer reviews form a gross filter or "early warning system". At one time, I would have sworn by Crucial Ballistix. Now, not so much. They've had their problems over the years. Which is why you check the customer reviews for "trending". Crucial had so much problems at one point, they stopped shipping Micron chips on the DIMMs, and started shipping Samsung. Just to give you some idea. Some manufacturers, are "rebranders" and don't actually make the RAM themselves. They don't actually have their own factory, churning out DIMMs. But what they do have, is a good contracting system, having the DIMMs made by third parties, tested, and then placing their own sticker on the RAM. If the contractor violates their trust relationship, they'll get turfed. Now, knowing that, imagine what the test results might mean. Sometimes, a SKU on Newegg, goes from "good" to "bad", on a lot basis. Some RAM manufacturers have changed chip source (when the "good" chips ran out), and if you're careful, you can spot the point in time that the modules became not worth buying. This tends to happen for DIMMs which extend past the official JEDEC range, and are "binned" or "made by binning" type products with elevated operating voltages. So if you were shopping for DDR3-2400, you might look for that in the customer reviews. We can't carry this "tea leaf" exercise too far. The idea is to spot trends or intelligence *if available*. For example, there was an issue at one time, with Micron D series silicon die, and a certain family of processor. To the point it might even have been mentioned on Anandtech. If you want, you can start sweeping the net (Anandtech forums, Xtremesystems.org forums) for that kind of knowledge. Using Newegg customer reviews, is an effort on my part, to make this data mining exercise less onerous. But if you *really* want to know a lot about RAM and RAM compatibility, then you'd spend the extra couple hours finding out that way. There are enthusiasts out there, who own twenty or thirty sets of RAM, and test them all. And when they spot a trend, or notice a problem with a new motherboard family, they can provide interesting input. This entry is a joke, but this is just to make a point. http://www.newegg.com/Product/Produc...82E16813131754 "3/16/2012 4:02:48 PM Awesome board! My ram wasn't on the list of compatible ram and it works fine." At one level, you select RAM based on specs. Does a motherboard family support all the RAM on the market ? DDR3 comes in "regular" or "reduced voltage" RAM. At one time, Intel supported both and AMD supported one of those. So one of your checks, would be to see whether the broadest range of RAM is supported. From the user manual for the motherboard: "DRAM Voltage[Auto] Allows you to set the DRAM voltage. The values range 1.20V to 2.20V" So that tells me the board (depending on CPU type), can support DDR3L. DDR3 nominal would be 1.5V, but there was some RAM where the voltage spec is centered at 1.35V. So it looks like that board is intended to cover both types. (The CPU actually determines whether the support is there, but tracking this down now on the AMD site, would be next to impossible.) You do the best you can, to data mine before buying. It could still happen, that you get a dud, or mismatch between your board and the RAM purchase. The purpose of JEDEC standards, is to try to make this process as painless as possible (broadest compatibility), which is why you don't absolutely need to use the Asus memory compatibility chart. But it makes some people feel better. When I clicked the download link for M5A99X Evo memory chart (from support.asus.com), this is the URL of the download. It would appear they just copied the test results, from another motherboard. http://dlcdnet.asus.com/pub/ASUS/mb/...Memory_QVL.zip To give another example of a "detected trend", when 2GB modules first came out, the BIOS simply wasn't set up on any board to properly handle them. The 1GB modules might work fine for you, while the 2GB, you could try all the tuning parameters on the board, and not get the RAM stable. I have a motherboard here, with that problem (that machine still has only 1GB modules in it). As BIOS updates were handed out, this problem gradually disappeared. And that observation, at the time, would have influenced a RAM purchase (i.e. you would buy 4x1GB instead of 2x2GB, until they fixed that). If you *didn't* read the enthusiast tea leaves at the time, you would have missed that, and ended up with lots of crashing misery. The Newegg's of the world, didn't stop selling 2GB modules, while the problem existed. It was eventually resolved, but in fact, not on my motherboard :-( The 2GB modules are now in my current machine, where they work fine. Paul Having 2nd thoughts about the motherboard. How do the following compare ... ASUS Sabertooth 990FX AM3+ AMD 990FX SATA 6Gb/s USB 3.0 ATX AMD Motherboard http://www.newegg.com/Product/Produc...82E16813131736 ASUS Crosshair V Formula AM3+ AMD 990FX SATA 6Gb/s USB 3.0 ATX AMD Gaming Motherboard http://www.newegg.com/Product/Produc...82E16813131735 ASUS M5A99X EVO AM3+ AMD 990X SATA 6Gb/s USB 3.0 ATX AMD Motherboard http://www.newegg.com/Product/Produc...82E16813131754 |
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need RAM recommendation - please help
Adam wrote:
Having 2nd thoughts about the motherboard. How do the following compare ... ASUS Sabertooth 990FX AM3+ AMD 990FX SATA 6Gb/s USB 3.0 ATX AMD Motherboard http://www.newegg.com/Product/Produc...82E16813131736 ASUS Crosshair V Formula AM3+ AMD 990FX SATA 6Gb/s USB 3.0 ATX AMD Gaming Motherboard http://www.newegg.com/Product/Produc...82E16813131735 ASUS M5A99X EVO AM3+ AMD 990X SATA 6Gb/s USB 3.0 ATX AMD Motherboard http://www.newegg.com/Product/Produc...82E16813131754 I don't know what your objectives are for the build. The chipsets differ in the PCI Express configuration. http://en.wikipedia.org/wiki/AMD_900_chipset_series "990FX * PCI Express 2.0 (2x16 or 4x8 configurations) * Support for up to 4 graphics cards * 19.6 Watt TDP * Southbridge: SB950 990X * PCI Express 2.0 (1x16 or 2x8 configurations) * Support for up to 2 graphics cards * 14 Watt TDP * Southbridge: SB950" Some of the peripheral chips might be a deciding factor (like if the external USB3 chips selected weren't the best). But it's possible they might be equal in terms of running a given processor at stock speeds. But you'll have to fill me in on what your expectations are. If you needed lots of PCI Express bandwidth, then the 990FX is probably a good way to get it. You pay for it, with a little bit extra Northbridge power usage. The motherboard reputations aren't markedly different. I think the most expensive board got a few more low ratings, because when an expensive board fails expectations, people usually judge it harshly. When I bought a $65 motherboard, nobody really hated that one, because, well, it was only $65, and what do you expect for $65. And that board still works :-) Paul |
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need RAM recommendation - please help
"Paul" wrote in message ... Adam wrote: Having 2nd thoughts about the motherboard. How do the following compare ... ASUS Sabertooth 990FX AM3+ AMD 990FX SATA 6Gb/s USB 3.0 ATX AMD Motherboard http://www.newegg.com/Product/Produc...82E16813131736 ASUS Crosshair V Formula AM3+ AMD 990FX SATA 6Gb/s USB 3.0 ATX AMD Gaming Motherboard http://www.newegg.com/Product/Produc...82E16813131735 ASUS M5A99X EVO AM3+ AMD 990X SATA 6Gb/s USB 3.0 ATX AMD Motherboard http://www.newegg.com/Product/Produc...82E16813131754 I don't know what your objectives are for the build. The chipsets differ in the PCI Express configuration. http://en.wikipedia.org/wiki/AMD_900_chipset_series "990FX * PCI Express 2.0 (2x16 or 4x8 configurations) * Support for up to 4 graphics cards * 19.6 Watt TDP * Southbridge: SB950 990X * PCI Express 2.0 (1x16 or 2x8 configurations) * Support for up to 2 graphics cards * 14 Watt TDP * Southbridge: SB950" Some of the peripheral chips might be a deciding factor (like if the external USB3 chips selected weren't the best). But it's possible they might be equal in terms of running a given processor at stock speeds. But you'll have to fill me in on what your expectations are. If you needed lots of PCI Express bandwidth, then the 990FX is probably a good way to get it. You pay for it, with a little bit extra Northbridge power usage. The motherboard reputations aren't markedly different. I think the most expensive board got a few more low ratings, because when an expensive board fails expectations, people usually judge it harshly. When I bought a $65 motherboard, nobody really hated that one, because, well, it was only $65, and what do you expect for $65. And that board still works :-) Paul Thanks (Guru Paul), so far, here is the components list ... - ASUS M5A99X Evo - AM3+ - 990X - ATX DDR3 2133 Motherboards [under consideration] - G.SKILL Ripjaws X Series 16GB (4 x 4GB) 240-Pin DDR3 1600 (PC3 12800) [under consideration] - AMD Phenom II X4 [under consideration; will run processor at stock speeds] - Sapphire 100315L Radeon HD 6850 Video Card [already own; will be single video card system] - OCZ ModXStream Pro 600W Modular High Performance Power Supply [already own] - Antec Three Hundred ATX Mid Tower Gaming Computer Case [already own] Objective is getting the best bang for the buck. |
#4
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need RAM recommendation - please help
Adam wrote:
"Paul" wrote in message ... Adam wrote: Having 2nd thoughts about the motherboard. How do the following compare ... ASUS Sabertooth 990FX AM3+ AMD 990FX SATA 6Gb/s USB 3.0 ATX AMD Motherboard http://www.newegg.com/Product/Produc...82E16813131736 ASUS Crosshair V Formula AM3+ AMD 990FX SATA 6Gb/s USB 3.0 ATX AMD Gaming Motherboard http://www.newegg.com/Product/Produc...82E16813131735 ASUS M5A99X EVO AM3+ AMD 990X SATA 6Gb/s USB 3.0 ATX AMD Motherboard http://www.newegg.com/Product/Produc...82E16813131754 I don't know what your objectives are for the build. The chipsets differ in the PCI Express configuration. http://en.wikipedia.org/wiki/AMD_900_chipset_series "990FX * PCI Express 2.0 (2x16 or 4x8 configurations) * Support for up to 4 graphics cards * 19.6 Watt TDP * Southbridge: SB950 990X * PCI Express 2.0 (1x16 or 2x8 configurations) * Support for up to 2 graphics cards * 14 Watt TDP * Southbridge: SB950" Some of the peripheral chips might be a deciding factor (like if the external USB3 chips selected weren't the best). But it's possible they might be equal in terms of running a given processor at stock speeds. But you'll have to fill me in on what your expectations are. If you needed lots of PCI Express bandwidth, then the 990FX is probably a good way to get it. You pay for it, with a little bit extra Northbridge power usage. The motherboard reputations aren't markedly different. I think the most expensive board got a few more low ratings, because when an expensive board fails expectations, people usually judge it harshly. When I bought a $65 motherboard, nobody really hated that one, because, well, it was only $65, and what do you expect for $65. And that board still works :-) Paul Thanks (Guru Paul), so far, here is the components list ... - ASUS M5A99X Evo - AM3+ - 990X - ATX DDR3 2133 Motherboards [under consideration] - G.SKILL Ripjaws X Series 16GB (4 x 4GB) 240-Pin DDR3 1600 (PC3 12800) [under consideration] - AMD Phenom II X4 [under consideration; will run processor at stock speeds] - Sapphire 100315L Radeon HD 6850 Video Card [already own; will be single video card system] - OCZ ModXStream Pro 600W Modular High Performance Power Supply [already own] - Antec Three Hundred ATX Mid Tower Gaming Computer Case [already own] Objective is getting the best bang for the buck. The only USB3 I know of, with a few problems, is Etron brand. http://forums.tweaktown.com/asrock/4...0-problem.html The M5A99X uses an Asmedia USB3 chip (a company which as far as I know, is a subsidiary of Asus). M5A99X EVO: 990X (1x16 or 2x8 video config) SB950 (6 SATA III, No USB3) (2) JMB362 (2 SATA II each) RealTek 8111E (Ethernet NIC) RealTek ALC892 (As long as you get at least stereo sound, you win...) (2) AsMedia USB3 (four ports total, two ports full bandwidth) VIA 6308P Firewire (Best were TI brand, or Lucent/Agere/LSI) Of your PCI Express slots, install the video card in the top slot, leave the second video card slot blank (to preserve the x16 interface rate), then you can use the x4 black slot for things like a RAID card perhaps. So the only shortcoming, is whether you consider the video card slot running at x8 to be a problem or not. x8 at PCI Express Rev2.0 rates, is 4GB/sec (8 lanes times 500MB/sec transfer rate). Check the reviews, see if the board has problems at higher memory clock speeds, and perhaps you have a winner. That board is certainly cheaper than the others. And the chipset will run cooler. With regard to the RAM, and how I'd run it, I'd buy the 4x4GB kit (because DDR3 is cheap, but the price will rise as one of the memory companies just got bought out). I'd operate the motherboard with just two sticks (8GB). Then keep the other two sticks as spares. Leaving two slots blank, improves cooling around the memory slots. If you have a problem with the 8GB, you just swap in the other pair. No downtime. I bought a set of 8 DIMMs once, and three have failed. Leaving me with five good ones :-) The last RAM I bought, with zero failures, was in the FPM/EDO era. Where it used to cost $600 to fill the computer with RAM. RAM just doesn't hold up any more. Paul |
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need RAM recommendation - please help
"Paul" wrote in message ... Adam wrote: "Paul" wrote in message ... Adam wrote: Having 2nd thoughts about the motherboard. How do the following compare ... ASUS Sabertooth 990FX AM3+ AMD 990FX SATA 6Gb/s USB 3.0 ATX AMD Motherboard http://www.newegg.com/Product/Produc...82E16813131736 ASUS Crosshair V Formula AM3+ AMD 990FX SATA 6Gb/s USB 3.0 ATX AMD Gaming Motherboard http://www.newegg.com/Product/Produc...82E16813131735 ASUS M5A99X EVO AM3+ AMD 990X SATA 6Gb/s USB 3.0 ATX AMD Motherboard http://www.newegg.com/Product/Produc...82E16813131754 I don't know what your objectives are for the build. The chipsets differ in the PCI Express configuration. http://en.wikipedia.org/wiki/AMD_900_chipset_series "990FX * PCI Express 2.0 (2x16 or 4x8 configurations) * Support for up to 4 graphics cards * 19.6 Watt TDP * Southbridge: SB950 990X * PCI Express 2.0 (1x16 or 2x8 configurations) * Support for up to 2 graphics cards * 14 Watt TDP * Southbridge: SB950" Some of the peripheral chips might be a deciding factor (like if the external USB3 chips selected weren't the best). But it's possible they might be equal in terms of running a given processor at stock speeds. But you'll have to fill me in on what your expectations are. If you needed lots of PCI Express bandwidth, then the 990FX is probably a good way to get it. You pay for it, with a little bit extra Northbridge power usage. The motherboard reputations aren't markedly different. I think the most expensive board got a few more low ratings, because when an expensive board fails expectations, people usually judge it harshly. When I bought a $65 motherboard, nobody really hated that one, because, well, it was only $65, and what do you expect for $65. And that board still works :-) Paul Thanks (Guru Paul), so far, here is the components list ... - ASUS M5A99X Evo - AM3+ - 990X - ATX DDR3 2133 Motherboards [under consideration] - G.SKILL Ripjaws X Series 16GB (4 x 4GB) 240-Pin DDR3 1600 (PC3 12800) [under consideration] - AMD Phenom II X4 [under consideration; will run processor at stock speeds] - Sapphire 100315L Radeon HD 6850 Video Card [already own; will be single video card system] - OCZ ModXStream Pro 600W Modular High Performance Power Supply [already own] - Antec Three Hundred ATX Mid Tower Gaming Computer Case [already own] Objective is getting the best bang for the buck. The only USB3 I know of, with a few problems, is Etron brand. http://forums.tweaktown.com/asrock/4...0-problem.html The M5A99X uses an Asmedia USB3 chip (a company which as far as I know, is a subsidiary of Asus). M5A99X EVO: 990X (1x16 or 2x8 video config) SB950 (6 SATA III, No USB3) (2) JMB362 (2 SATA II each) RealTek 8111E (Ethernet NIC) RealTek ALC892 (As long as you get at least stereo sound, you win...) (2) AsMedia USB3 (four ports total, two ports full bandwidth) VIA 6308P Firewire (Best were TI brand, or Lucent/Agere/LSI) Of your PCI Express slots, install the video card in the top slot, leave the second video card slot blank (to preserve the x16 interface rate), then you can use the x4 black slot for things like a RAID card perhaps. So the only shortcoming, is whether you consider the video card slot running at x8 to be a problem or not. x8 at PCI Express Rev2.0 rates, is 4GB/sec (8 lanes times 500MB/sec transfer rate). Check the reviews, see if the board has problems at higher memory clock speeds, and perhaps you have a winner. That board is certainly cheaper than the others. And the chipset will run cooler. With regard to the RAM, and how I'd run it, I'd buy the 4x4GB kit (because DDR3 is cheap, but the price will rise as one of the memory companies just got bought out). I'd operate the motherboard with just two sticks (8GB). Then keep the other two sticks as spares. Leaving two slots blank, improves cooling around the memory slots. If you have a problem with the 8GB, you just swap in the other pair. No downtime. I bought a set of 8 DIMMs once, and three have failed. Leaving me with five good ones :-) The last RAM I bought, with zero failures, was in the FPM/EDO era. Where it used to cost $600 to fill the computer with RAM. RAM just doesn't hold up any more. Paul Thanks (Guru Paul), regarding USB3, I had USB3 issues with my Asus laptop and had to downgrade the only USB3 port to use USB2. Luckily, I don't own many USB3 devices yet. Perhaps, USB3 is a general issue (with Asus and other brands)? Not sure I understand this part ... So the only shortcoming, is whether you consider the video card slot running at x8 to be a problem or not. x8 at PCI Express Rev2.0 rates, is 4GB/sec (8 lanes times 500MB/sec transfer rate). Is the video card being restricted (hopefully not)? I don't play games much but do plan to watch videos. How much better will the Sabertooth be? Great idea about the RAM (and using only 2 slots first). Check the reviews, see if the board has problems at higher memory clock speeds, and perhaps you have a winner. That board is certainly cheaper than the others. And the chipset will run cooler. I tend to run things at stock speeds so no overclocking issue? |
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need RAM recommendation - please help
Adam wrote:
Not sure I understand this part ... So the only shortcoming, is whether you consider the video card slot running at x8 to be a problem or not. x8 at PCI Express Rev2.0 rates, is 4GB/sec (8 lanes times 500MB/sec transfer rate). Is the video card being restricted (hopefully not)? I don't play games much but do plan to watch videos. How much better will the Sabertooth be? Great idea about the RAM (and using only 2 slots first). Check the reviews, see if the board has problems at higher memory clock speeds, and perhaps you have a winner. That board is certainly cheaper than the others. And the chipset will run cooler. I tend to run things at stock speeds so no overclocking issue? There are two decent PCI Express slots on the M5A99X EVO. If you insert a video card in the upper slot, and place *no card* in the second slot, the video card runs x16. x16 none If you were to plug an x1 TV tuner card into the second video card slot, that would immediately cause the top video card slot to run at x8. x8 x8 --- I just plugged my TV tuner card in... Some people care about that, but I don't. x8 should still be enough. But some people don't like it. So if you leave the second video card slot blank, then the top slot continues to run x16. A gamer might like it this way. x16 none The third slot, is permanently wired x4. Even though the slot is x16 in size, only x4 of the lanes are wired. And you can visually see this, in motherboard pictures, by counting the ceramic coupling capacitors next to the video slot. A x16 capable slot, would have at least 16 "blobs" adjacent to the slot. An x8 capable slot, at least 8 blobs. And so on. The x16 slot with x4 wiring, would have 4 "blobs" next to it. http://www.ixbt.com/mainboard/asus/m5a99x-evo/board.jpg (Slot wiring circled...) http://img713.imageshack.us/img713/9...iringcheck.gif Pinout of PCI Express, so you can see why I'm circling those things. http://media.bestofmicro.com/A/L/101...e-slot-big.gif The PCI Express lanes are capacitively coupled. Which is why those blobs are present. The capacitors must be placed, within a certain distance of the slot, so they don't typically appear at arbitrary spots. And since PCI Express lanes are bidirectional (separate pair of TX wires, from separate pair of RX wires), the other matching "blobs" are on the video card end, near the GPU. PCI Express host --- cap --------------------- PCI Express --- cap --------------------- peripheral card --------------------- cap --- --------------------- cap --- Each pair of wires = 500MB/sec The PCI Express is "full duplex", meaning the card can talk to the processor, at the same time as the processor is sending something to the card. Paul |
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need RAM recommendation - please help
"Paul" wrote in message ... Adam wrote: Not sure I understand this part ... So the only shortcoming, is whether you consider the video card slot running at x8 to be a problem or not. x8 at PCI Express Rev2.0 rates, is 4GB/sec (8 lanes times 500MB/sec transfer rate). Is the video card being restricted (hopefully not)? I don't play games much but do plan to watch videos. How much better will the Sabertooth be? Great idea about the RAM (and using only 2 slots first). Check the reviews, see if the board has problems at higher memory clock speeds, and perhaps you have a winner. That board is certainly cheaper than the others. And the chipset will run cooler. I tend to run things at stock speeds so no overclocking issue? There are two decent PCI Express slots on the M5A99X EVO. If you insert a video card in the upper slot, and place *no card* in the second slot, the video card runs x16. x16 none If you were to plug an x1 TV tuner card into the second video card slot, that would immediately cause the top video card slot to run at x8. x8 x8 --- I just plugged my TV tuner card in... Some people care about that, but I don't. x8 should still be enough. But some people don't like it. So if you leave the second video card slot blank, then the top slot continues to run x16. A gamer might like it this way. x16 none The third slot, is permanently wired x4. Even though the slot is x16 in size, only x4 of the lanes are wired. And you can visually see this, in motherboard pictures, by counting the ceramic coupling capacitors next to the video slot. A x16 capable slot, would have at least 16 "blobs" adjacent to the slot. An x8 capable slot, at least 8 blobs. And so on. The x16 slot with x4 wiring, would have 4 "blobs" next to it. http://www.ixbt.com/mainboard/asus/m5a99x-evo/board.jpg (Slot wiring circled...) http://img713.imageshack.us/img713/9...iringcheck.gif Pinout of PCI Express, so you can see why I'm circling those things. http://media.bestofmicro.com/A/L/101...e-slot-big.gif The PCI Express lanes are capacitively coupled. Which is why those blobs are present. The capacitors must be placed, within a certain distance of the slot, so they don't typically appear at arbitrary spots. And since PCI Express lanes are bidirectional (separate pair of TX wires, from separate pair of RX wires), the other matching "blobs" are on the video card end, near the GPU. PCI Express host --- cap --------------------- PCI Express --- cap --------------------- peripheral card --------------------- cap --- --------------------- cap --- Each pair of wires = 500MB/sec The PCI Express is "full duplex", meaning the card can talk to the processor, at the same time as the processor is sending something to the card. Paul Thanks (Guru Paul), I just canceled my order for M5A99X EVO since I would like a motherboard with more room for growth (or more PCI Express slots). Any CPU/motherboard combo suggestions? |
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need RAM recommendation - please help
Adam wrote:
Thanks (Guru Paul), I just canceled my order for M5A99X EVO since I would like a motherboard with more room for growth (or more PCI Express slots). Any CPU/motherboard combo suggestions? Without spending any time on it, this is the "most PCI Express" I could find. http://www.newegg.com/Product/Produc...82E16813128508 Note that it still uses the 990FX chipset. I think that chipset has max total, about 42 lanes or so. Even the official looking diagrams on the web, aren't complete. The thing is, you can "fan out" lanes, but the max bandwidth available doesn't change. Say, for example, I do this. x16 ----- Switch ---- x16 (card) host Chip ------ x16 (card) If both cards start transferring at the same time, each will average x8 transfer rate. You cannot make something from nothing. So when the chipset starts with 42 lanes, you cannot use chips downstream of that, to make more bandwidth. The number of lanes may *seem* larger, but depending on the transfer conditions, the average rates achieved on the cards are still influenced by the "narrowest piece of pipe". To get a summary of the wiring pattern there, we don't trust the Newegg table. This calls for the motherboard manual. ftp://download.gigabyte.ru/manual/mb...0fxa-ud7_e.pdf And even that might not be enough. This is the block diagram. The official diagram is missing a detail. This is my best guess now. I got a double-check on ALink from here. http://compare-processors.com/wp-con...chitecture.png CPU | | 6.4GT/sec * 2bytes/T = 12.8GB/sec | Northbridge --- x16 ---- slot | 990FX ---- slot | --- x16 ---- slot | ---- slot | | ---- x6 (flexible) | | ALink 2GB/sec | Southbridge ---- x4 (flexible) SB950 The first thing to notice in such a diagram, is the CPU connection to the outside world, is limited by Hypertransport. Now, the claim I see, is the current transfer rate is 6.4 giga-transfers per second. And that bus is 16 bits or 2 bytes wide. So the processor, when sending bus traffic in one of the directions, cannot exceed 12.8GB/sec when doing so. If I take 12800 and divide by the 500 per PCI Express lane, that equals 25.6 lanes. That means, the bottom part of the diagram has 42 lanes, but the processor "bottleneck" supports at maximum 25.6 worth. The second bottleneck, is the ALink. There are 4x500 for the four PCI Express lanes off the Southbridge. But, there are other "loads" on the Southbridge, such as your SATA drives. Say, for example, you start a read on your 550MB/sec SATA III SSD, at the same time as the x4 on the side are doing something. There is a small chance of a bottleneck there. When there is a bottleneck, nothing breaks, it just runs slower. Like, when you step on a hose, and there is a lesser trickle of water from the hose nozzle. The impressive motherboard above, has the same restriction as the motherboard you were just looking at. Two video cards Two video cards and two blanks and two TV tuners -------------- ----------------- x16 x8 None x8 --- just installed Tuner x16 x8 None x8 --- just installed Tuner So that covers the restrictions on four of the slots. It has twice as many slots for video, as the cheaper motherboard, but the same style of restriction when all four have something plugged in. Now, try to figure out what remains. There are five PCI Express peripheral chips. We have x6 left on top, x4 left on the bottom. 10 - 5 = 5 left. Yet, there are two x4 PCI Express slots, for a total of 8 lanes. That means those 8 lanes can't be "real". The Gigabyte diagram says something like this, but there isn't a "switch" shown feeding the two x4 slots. NB x6 --- x1 Etron EJ168 USB3 --- x1 88SE9172 --- x4 ------------------ switch --- x4 --- x4 SB x4 --- x1 Etron EJ168 USB3 --- x1 88SE9172 --- x1 RealTek RTL8111E NIC --- x1 (unused???) Notice that the two x4 slots, are sharing. If, for some reason, one wants to run x4, it can. But if both start transferring at the same time (unlikely, actually), then they'd be limited to x2 each. So even a fancy board, using the best (42 lane) chipset on AMD you can find, is left wanting in places. But at least you can say, "two video cards can be run at x16 each". Subject to the bottleneck where the CPU connects to things. So each card can have 6.4GB/sec average, if both were transferring at the same time (say, some Crossfire operation). HTH, Paul |
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Thread | Thread Starter | Forum | Replies | Last Post |
need RAM recommendation - please help | Adam | Homebuilt PC's | 34 | July 4th 12 08:28 PM |
need RAM recommendation - please help | Adam | Asus Motherboards | 3 | July 2nd 12 12:05 AM |
need RAM recommendation - please help | Adam | Asus Motherboards | 0 | June 30th 12 09:16 PM |
P4C800-E Deluxe - Ram Recommendation? | BobMarley | Asus Motherboards | 4 | October 24th 03 06:16 PM |