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#1
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How it is possible
How it is possible that one SSD is 17 times as fast as another but costs
less? Both are 240G. Why would anyone buy the slower one (like I did last summer)? https://www.amazon.com/dp/B01N5IB20Q...t_details&th=1 350 Mb per second $35 https://www.amazon.com/PNY-CS900-240...01N5IB20Q?th=1 6 Gb per second $30 plus $6 for a bracket if you need one. In the comparison list of the first one, 4 of them side by side, half way to the bottom of the page, 2 others are the same speed as the first, but the second one is 17 times as fast. In a similar side-by-side comparison list on the second page, the same thing is true. Only the PNY is so fast, and for less money. Does PNY know something the others don't know. |
#2
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How it is possible
On 3/7/2021 2:12 PM, micky wrote:
How it is possible that one SSD is 17 times as fast as another but costs less? Both are 240G. Why would anyone buy the slower one (like I did last summer)? https://www.amazon.com/dp/B01N5IB20Q...t_details&th=1 350 Mb per second $35 https://www.amazon.com/PNY-CS900-240...01N5IB20Q?th=1 6 Gb per second $30 plus $6 for a bracket if you need one. In the comparison list of the first one, 4 of them side by side, half way to the bottom of the page, 2 others are the same speed as the first, but the second one is 17 times as fast. In a similar side-by-side comparison list on the second page, the same thing is true. Only the PNY is so fast, and for less money. Does PNY know something the others don't know. I have two suggestions: 1) follow the two URLs you provided and read carefully - there is little difference between the two advertised read speeds and 2) note that MB and Mb are different by a factor of eight as are GB and Gb. Confusion between the latter two has many proud computer scientist bragging about their Gigabyte LAN; it's really Gigabit and that's quite different. -- Jeff Barnett |
#3
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How it is possible
On Sun, 07 Mar 2021 16:12:25 -0500, micky wrote:
How it is possible that one SSD is 17 times as fast as another but costs less? Both are 240G. Why would anyone buy the slower one (like I did last summer)? https://www.amazon.com/dp/B01N5IB20Q...t_details&th=1 350 Mb per second $35 https://www.amazon.com/PNY-CS900-240...01N5IB20Q?th=1 6 Gb per second $30 plus $6 for a bracket if you need one. The first drive has a read speed of 500 Megabytes Per Second. The second 535, so only slightly faster. A sata iii Hardware Interface works with a sata iii controller that supports a max bus speed of 6 Gb. See https://en.wikipedia.org/wiki/Serial_ATA The first drive is actually a sata ii drive, the second sata iii. The term "Style" has no technical meaning. It's just a marketing term. The hardware interface speed tells you whether it's sata, sata ii, or sata iii. Newer drives are often lower in price per MB than older ones. Regards, Dave Hodgins -- Change to for email replies. |
#4
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How it is possible
On Sun, 7 Mar 2021 at 16:12:25, micky wrote (my
responses usually follow points raised): How it is possible that one SSD is 17 times as fast as another but costs less? Both are 240G. Why would anyone buy the slower one (like I did last summer)? [] In the comparison list of the first one, 4 of them side by side, half way to the bottom of the page, 2 others are the same speed as the first, but the second one is 17 times as fast. In a similar side-by-side comparison list on the second page, the same thing is true. Only the PNY is so fast, and for less money. Does PNY know something the others don't know. Even leaving aside Jeff's point about bits versus bytes, speed isn't the only important parameter for and SSD: there are probably many, but the one that bugs me is the tolerated number of writes - which for the same size SSD in the same machine/use, more or less maps to lifetime. You also need to know how they behave when they reach their end of life: do they continue trying to work (I don't think any), switch to read-only, or just become a brick (at least one make/range does). -- J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf A leader who keeps his ear to the ground allows his rear end to become a target. - Angie Papadakis |
#5
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How it is possible
In article , J. P. Gilliver (John)
wrote: Even leaving aside Jeff's point about bits versus bytes, speed isn't the only important parameter for and SSD: there are probably many, but the one that bugs me is the tolerated number of writes - which for the same size SSD in the same machine/use, more or less maps to lifetime. an ssd will very likely outlast the computer it's in, certainly a lot longer than a spinning hard drive would have, and with a lot less noise and heat. You also need to know how they behave when they reach their end of life: do they continue trying to work (I don't think any), switch to read-only, many do. or just become a brick (at least one make/range does). that's what backups are for. drive failure is not unique to ssd. hard drives crashed, often without warning. |
#6
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How it is possible
micky wrote:
How it is possible that one SSD is 17 times as fast as another but costs less? Both are 240G. Why would anyone buy the slower one (like I did last summer)? https://www.amazon.com/dp/B01N5IB20Q...t_details&th=1 350 Mb per second $35 https://www.amazon.com/PNY-CS900-240...01N5IB20Q?th=1 6 Gb per second $30 plus $6 for a bracket if you need one. In the comparison list of the first one, 4 of them side by side, half way to the bottom of the page, 2 others are the same speed as the first, but the second one is 17 times as fast. In a similar side-by-side comparison list on the second page, the same thing is true. Only the PNY is so fast, and for less money. Does PNY know something the others don't know. Do you know the difference between a bit and a byte? The first SSD says its read spead is 500 MB/s (not 350 Mb/s). Multiply 500 MB/s by 8 to get Mb/s second, and what do you get? 4 Gb/s which is not far from the rating for the other SSD. In addition, the read spec for the PNY SSD is not the 6 Gb/s you stated, but 535 MB/s as stated by the Amazon ad, so its read speed would be 8 x 535 MB/s = 4.3 Gb/s. You also need to consider the brand of the SSD. You are comparing Kingston to PNY. PNY is okay, but has higher fail rates (from my personal experience) than for Kingston. This is brand, not by whomever is the actual manufacturer on which a brand slaps on its sticker. Brands can contract specs with the manufacturer: the same maker can produce different quality products based on what the customer specifies. Is it your custom to compare normal retail price against sale price? The PNY is on sale. It's non-sale price is $40 which is higher than the Kingston product. Sales come and go. Compare apples to apples. Even you know your grocery store has sales, but that's not the normal price. Next time, drink a cup of coffee an hour before researching SSD prices and specs. Don't compare MB/s to GB/s unless you convert. Don't compare sale with non-sale price. Today, for you, was one those "Oops" days. |
#7
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How it is possible
On 07/03/2021 21:12, micky wrote:
How it is possible that one SSD is 17 times as fast as another but costs less? Both are 240G. Why would anyone buy the slower one (like I did last summer)? https://www.amazon.com/dp/B01N5IB20Q...t_details&th=1 350 Mb per second $35 https://www.amazon.com/PNY-CS900-240...01N5IB20Q?th=1 6 Gb per second $30 plus $6 for a bracket if you need one. I'm not sure how you're reading them differently, but the 6Gbps is the *interface* speed for SATA3 and is not the *device* speed. In terms of device performance the PNY and Kingston are both ~500 Mbps so I don't see where you get the 350 Mbps from? In the comparison list of the first one, 4 of them side by side, half way to the bottom of the page, 2 others are the same speed as the first, but the second one is 17 times as fast. Again, you're being spectacularly vague. With sites like Amazon it is almost impossible to know what someone sees as it dependent on their history, country of origin, what device they're viewing it on, time of day, etc. so I'm not seeing what you're seeing. On the Kingston page I see the comparison of four different models: A400 SATA 3 2.5", A400 M.2 SATA 3, A2000 NVMe, HyperX Fury RGB SSD. In terms of read/write speed they're all fairly similar (450-550 Mbps) except the 'A2000 NVme which is 'upto 2000 Mbps'. Which is unsurprising given that it uses the NVMe interface which is spectacularly fast. In choosing an SSD you need make sure you get one which matches both the form factor (2.5" internal, 2.5" external, M.2) and interface (USB, eSATA, SATA, M.2, NVMe) that you need. Only then do you look at price. |
#8
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How it is possible
micky wrote:
How it is possible that one SSD is 17 times as fast as another but costs less? Both are 240G. Why would anyone buy the slower one (like I did last summer)? https://www.amazon.com/dp/B01N5IB20Q...t_details&th=1 350 Mb per second $35 https://www.amazon.com/PNY-CS900-240...01N5IB20Q?th=1 6 Gb per second $30 plus $6 for a bracket if you need one. In the comparison list of the first one, 4 of them side by side, half way to the bottom of the page, 2 others are the same speed as the first, but the second one is 17 times as fast. In a similar side-by-side comparison list on the second page, the same thing is true. Only the PNY is so fast, and for less money. Does PNY know something the others don't know. Wire speed of interface: 6 gbit/sec * 8/10 * 1/8 = 600MB/sec (goodput rate) 8B10B bits per bytes encode DC Balance The SATA connector with the seven pins, uses packets. The packets are like "request" and "acknowledge". There are time gaps between packets. Using tagged queueing, more than one transfer can be in motion at once. This makes it easier for the link to find something to do. But the usable rate with the packets, is about 500MB/sec or somewhere in that ballpark. No packet protocol goes exactly at 100.0% of link speed. There's always gaps of various sizes. Ethernet packets have pretty small gaps between them, but other things are quite bad at that, like USB2 (60MB/sec) runs mass storage protocol at 35MB/sec max. There are a few SATA controller chips (add-ons) that don't actually run at full speed either. There's a Marvell chip with SATA III interface, where it can only send the packets at ~300MB/sec. But things like Intel or AMD Southbridge SATA III aren't like that, and they're not likely to be the bottleneck. All of the hardware in those cases, can be capable of 500MB/sec of packets. ******* The Flash can only read and write, so fast. There is the page size and the number of Flash channels. Modern drives have relatively low chip counts. A small drive only has a couple flash chips plus a nice controller. This compares to a USB stick which has a couple flash chips and a crappy controller. (The SSD has ARM processor cores inside its controller. The USB2 chip has an 8085 in it. Comparatively speaking.) The quality metric is write speed. Maybe a drive reads at 535MB/sec (according to the label), but writes at 300MB/sec. If the drive uses TLC or QLC based flash, it may have a section of Flash that functions as a small cache (20GB perhaps). Any sustained transfer, runs at the cache speed. But if a sustained transfer (a Macrium backup .mrimg file maybe) exceeds 20GB in size, the drive slows down on writes a bit. A Samsung with "MLC-like" 3DNAND, the old ones really were MLC-like and the drive did not use a cache, and had uniform speed from end to end. Some of this years Samsung drives claim to be MLC-like but they're not. They're using Flash cache like everyone else, and Samsung falls off its pedestal. When they're forced to do that, that's evidence the thing is just TLC-like and not worth a dime extra. ******* Let's take my laptop as an example of how you could easily get carried away with this stuff. I buy a SATA III SSD at 500MB/sec, worried about getting shafted on a purchase. Yet, if we examine my SATA port in the laptop, it actually runs at SATA II speed, or half that (250MB/sec max). OK, so I buy a "300MB/sec write" SSD. See the problem ? The SSD is actually perfectly adequate for the job and "keeps up with the rate". Whether I ran either the 500MB/sec write SSD or the 300MB/sec write SSD, I can't tell the difference, because the laptop only does 250MB/sec on the wire. You didn't need the fancy one after all :-) And that's how my laptop goes. Gave it a SATA III SSD. Runs at SATA II rates. What a waste, eh ? Well, it's not entirely a waste. The main improvement in SSD drives, is the reduction in seek time. It takes no time to "move the heads". It doesn't matter how files are scattered over the SSD surface. Takes the same time to read them, no matter where they are. This is why we buy the SSD. Whether it writes at 300MB/sec or 250MB/sec, there could be times when that speed helps. But not every second the SSD is sitting there on the desktop, does it need to run flat out like that. Lots of SSD operation is in tiny bursts. It's not the end of the world if the sustained isn't "the speed of light". Sure, you notice the speed when you bench with HDTune. But for a lot of other uses, it's not so bad after all. All the SSDs are better than spinning rust, because of the seek time. You know how Windows 10 likes to "scan stuff for fun". That's a lot of seeks. And that's why we have SSDs for Windows 10. Speed up the boot might be the most impressive thing it does, all day long. Hardly noticed otherwise. Paul |
#9
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How it is possible
On 3/7/21 1:12 PM, micky wrote:
How it is possible that one SSD is 17 times as fast as another but costs less? Both are 240G. Why would anyone buy the slower one (like I did last summer)? https://www.amazon.com/dp/B01N5IB20Q...t_details&th=1 350 Mb per second $35 https://www.amazon.com/PNY-CS900-240...01N5IB20Q?th=1 6 Gb per second $30 plus $6 for a bracket if you need one. In the comparison list of the first one, 4 of them side by side, half way to the bottom of the page, 2 others are the same speed as the first, but the second one is 17 times as fast. In a similar side-by-side comparison list on the second page, the same thing is true. Only the PNY is so fast, and for less money. Does PNY know something the others don't know. Hi Micky, You pay for what you get. If you want the least likelihood the thing bricking on you, get a Samsung. -T |
#10
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How it is possible
On 08/03/2021 00.30, J. P. Gilliver (John) wrote:
On Sun, 7 Mar 2021 at 16:12:25, micky wrote (my responses usually follow points raised): How it is possible that one SSD is 17 times as fast as another but costs less?Â*Â* Both are 240G.Â*Â* Why would anyone buy the slower one (like I did last summer)? [] In the comparison list of the first one, 4 of them side by side, half way to the bottom of the page, 2 others are the same speed as the first, but the second one is 17 times as fast. In a similar side-by-side comparison list on the second page, the same thing is true.Â* Only the PNY is so fast, and for less money.Â* Does PNY know something the others don't know. Even leaving aside Jeff's point about bits versus bytes, speed isn't the only important parameter for and SSD: there are probably many, but the one that bugs me is the tolerated number of writes - which for the same size SSD in the same machine/use, more or less maps to lifetime. You also need to know how they behave when they reach their end of life: do they continue trying to work (I don't think any), switch to read-only, or just become a brick (at least one make/range does). Which one bricks? That's important to know. -- Cheers, Carlos. |
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