Motherboard, CPU, and Memory Timing Compatibility Match

I'm going to get an Asus Crosshair V Formula Z motherboard, and the
FX-6300 CPU from AMD. I have discovered that the motherboard supports
DDR3 2400 memory, while the CPU only supports DDR3 1866. As one who
doesn't like to run something for all it can do (like I don't drive my car
at its maximum speed), will it actually hurt anything to use the 2400
memory? If some other AM3+ processor comes out later that supports faster
memory, I'd like to be prepared for it by having the appropriate memory
ahead of time instead of having to buy it again later.

I don't mind if 2400 memory runs at 1866. I just don't want to have a
2400-capable processor later with 1866 memory installed. In the meantime,
I feel more comfortable running 2400 memory at 1866 because it'll be like
driving 70 miles an hour in a car that'll do 126 miles an hour.

Sorry if this sounds like a newbie question. I've actually built my last
three or four computers (I only bought my first PC off the shelf), so I
generally know what I'm doing, but sometimes I want to be double-sure
before I actually start spending money.

Thanks,
Damaeus

In news:alt.comp.hardware.pc-homebuilt, Damaeus
posted on Thu, 27 Dec 2012 19:45:04
-0600 the following:

Sorry if this sounds like a newbie question. I've actually built my last
three or four computers (I only bought my first PC off the shelf), so I
generally know what I'm doing, but sometimes I want to be double-sure
before I actually start spending money.

Woops, I might as well include this part, too:

I'm also going to try to set up a dual-boot with Windows 8 (64-bit) and
Windows XP (32-bit). Surely Windows XP won't complain about having extra
memory it can't use, right? I don't mind if XP doesn't use the extra
memory, but I still want it there for Windows 8.

Thanks again,
Damaeus

Damaeus wrote:
I'm going to get an Asus Crosshair V Formula Z motherboard, and the
FX-6300 CPU from AMD. I have discovered that the motherboard supports
DDR3 2400 memory, while the CPU only supports DDR3 1866. As one who
doesn't like to run something for all it can do (like I don't drive my car
at its maximum speed), will it actually hurt anything to use the 2400
memory? If some other AM3+ processor comes out later that supports faster
memory, I'd like to be prepared for it by having the appropriate memory
ahead of time instead of having to buy it again later.

I don't mind if 2400 memory runs at 1866. I just don't want to have a
2400-capable processor later with 1866 memory installed. In the meantime,
I feel more comfortable running 2400 memory at 1866 because it'll be like
driving 70 miles an hour in a car that'll do 126 miles an hour.

Sorry if this sounds like a newbie question. I've actually built my last
three or four computers (I only bought my first PC off the shelf), so I
generally know what I'm doing, but sometimes I want to be double-sure
before I actually start spending money.

Thanks,
Damaeus

Someone here is running the memory interface at DDR3-2164 at 1.63V.
Which suggests you can have a little fun with it.

http://www.overclock.net/t/1341479/f...ing-help-guide

If it's unlocked, you should be able to do core testing with
nothing more than a multiplier change. And some voltage if it
needs it. Then, back off on the core, and work on your memory
a bit, and see what it can handle.

Intel processors have a 1.65V suggested limit on the 1.5V DDR3
memory interface, but I don't know if AMD has the same problem
or not.

Paul

On 27/12/2012 8:45 PM, Damaeus wrote:
I'm going to get an Asus Crosshair V Formula Z motherboard, and the
FX-6300 CPU from AMD. I have discovered that the motherboard supports
DDR3 2400 memory, while the CPU only supports DDR3 1866. As one who
doesn't like to run something for all it can do (like I don't drive my car
at its maximum speed), will it actually hurt anything to use the 2400
memory? If some other AM3+ processor comes out later that supports faster
memory, I'd like to be prepared for it by having the appropriate memory
ahead of time instead of having to buy it again later.

No, DDR3 is DDR3, so you could either run DDR3 that is faster than your
processor is capable of, or slower too. The processor will simply read
the capabilities of the DDR3 module's SPD (Serial Presence Detect),
which includes the internal timings capabilities of that RAM module. The
CPU will then choose the fastest timing available.

Yousuf Khan

On 27/12/2012 8:47 PM, Damaeus wrote:
Woops, I might as well include this part, too:

I'm also going to try to set up a dual-boot with Windows 8 (64-bit) and
Windows XP (32-bit). Surely Windows XP won't complain about having extra
memory it can't use, right? I don't mind if XP doesn't use the extra
memory, but I still want it there for Windows 8.

XP won't complain about the memory, but you may find that such a newer
motherboard may not even include XP drivers for various things. You may
be lucky to get that system running with only a few non-critical Unknown
Devices in your Device Manager. People should be giving up their
obsession with XP by now, it's out of support. If you're absolutely
determined to dual-boot to an older Windows on it, then you're better
off making that older OS, Windows 7.

Yousuf Khan

In news:alt.comp.hardware.pc-homebuilt, Paul posted on
Thu, 27 Dec 2012 21:30:02 -0500 the following:

Someone here is running the memory interface at DDR3-2164 at 1.63V.
Which suggests you can have a little fun with it.

http://www.overclock.net/t/1341479/f...ing-help-guide

If it's unlocked, you should be able to do core testing with
nothing more than a multiplier change. And some voltage if it
needs it. Then, back off on the core, and work on your memory
a bit, and see what it can handle.

Thanks. Yes, I'd like some room to tinker around with overclocking if I
happen to gather the gumption. I'm not into "overclocking" or "system
tweaking" of voltages or timings or anything. I'm more into system
stability by running things the way they're designed to be run, and any
overclocking I don't use, in my view, becomes a system stability buffer.
It worked on my last computer. I don't want to run it just below the
point where it starts to crash or have errors, which is why it seems
sensible to me to have more than enough instead of buying just enough and
having the memory running at its maximum speed all the time it's being
accessed.

As it turns out, the 2400 Kingston memory I was looking at can only be
used in one pair on the motherboard I want. The 2133 Kingston, however,
can be stuck in all four DIMM slots. So I'll be running 2133 memory in a
2400 motherboard with an 1866 CPU. That actually sounds even better to
me.

I don't play a LOT of games, but I'm very impatient when it comes to
waiting for things to launch. So even if all I'm doing is starting my
e-mail program/newsreader, if I can shave just a second and a half off the
launch time, I'm totally elated....but not at the sacrifice of stability.
I hate crashes!

Thanks for the reply.

Damaeus

In news:alt.comp.hardware.pc-homebuilt, Yousuf Khan
posted on Fri, 28 Dec 2012 02:09:29 -0500 the
following:

No, DDR3 is DDR3, so you could either run DDR3 that is faster than your
processor is capable of, or slower too. The processor will simply read
the capabilities of the DDR3 module's SPD (Serial Presence Detect),
which includes the internal timings capabilities of that RAM module. The
CPU will then choose the fastest timing available.

Excellent. I'm not trashing RoG posters in the Asus RoG forum, but they
were suggesting 1600 memory as the "sweet spot", but in my way of
understanding, that would unecessarily bottleneck the CPU to 1600. I see
no reason to put any memory into the system that's slower than 1833 since
the CPU is an 1833 model. I admit to wondering, however, if they were
trying to sabotage my build with nefarious advice. I didn't accuse them
there, but the thought did cross my mind. It's kind of like my friend's
mom, who was told that to make the crispiest home-made pickles, you must
use VERY ripe cucumbers. Yet all the information I can find online says
the crispiest pickles come from cucumbers that are barely ripe. The way
some of those old bitties were in the old days, I just know some of them
wanted to have better pickles than everyone else, so the woman who told my
friend to use extremely ripe pickles may have been giving unsound advice
just to keep herself in the top position as the best pickle-maker in town.
How many times have you heard it about cookies? "I use the same recipe as
my grandmother did, but my cookies never turn out like hers!" Grandma
sabotaged the recipe, that's why! LOL I can imagine how some
computer-builders might have the same attitude. Your post makes more
sense than what I read in the Asus RoG forum and it's what I originally
thought before asking this type of question there. It's great to get a
variety of comments.

Thank you for your post!

Damaeus

In news:alt.comp.hardware.pc-homebuilt, Yousuf Khan
posted on Fri, 28 Dec 2012 02:15:07 -0500 the
following:

XP won't complain about the memory, but you may find that such a newer
motherboard may not even include XP drivers for various things. You may
be lucky to get that system running with only a few non-critical Unknown
Devices in your Device Manager. People should be giving up their
obsession with XP by now, it's out of support. If you're absolutely
determined to dual-boot to an older Windows on it, then you're better
off making that older OS, Windows 7.

I'm not really obsessed with XP. I'm ready to give it up completely, but
I've heard of issues running Final Fantasy XI in Windows 8. When
researching the web for any problems people are having with that game in
Windows 8, the most common problem I saw people posting about was that the
character models are not showing up in the game, not for players or for
monsters. So I know that FFXI works great in XP, so the only reason I
want XP hanging around is for that one game. If I had more cash, I would
be willing to get Windows 7, but with the few other hardware items I need
to get (SATA DVD burner, front-panel card-reater with USB ports, new PCIe
TV tuner to replace my PCI TV tuner), buying a full retail version of
Windows 7 isn't a good choice right now and I probably won't have enough
money for it. Besides, I want a little left over for a certain dried
plant that works wonders when turned into smoke.

Damaeus

In news:alt.comp.hardware.pc-homebuilt, Yousuf Khan
posted on Fri, 28 Dec 2012 02:15:07 -0500 the
following:

People should be giving up their obsession with XP by now, it's out of
support.

Oh, XP is still supported, by the way. I still get update notifications
from Microsoft's update. I know that won't last forever, but it's still
working now. I know they discontinued support for XP for a while, but
they re-instated it, I guess because so many people complained.

I read somewhere that Windows 9 is going to be a yearly subscription
service. I guess that's so they can extend support for as long as people
are willing to continue paying the subscription fees. And if upgrades
become "free" (or virtually free), more people might be willing to upgrade
and Microsoft can save money by not having crews working on updates for so
many versions of Windows.

/assumption

Damaeus

Damaeus wrote:
In news:alt.comp.hardware.pc-homebuilt, Paul posted on
Thu, 27 Dec 2012 21:30:02 -0500 the following:

Someone here is running the memory interface at DDR3-2164 at 1.63V.
Which suggests you can have a little fun with it.

http://www.overclock.net/t/1341479/f...ing-help-guide

If it's unlocked, you should be able to do core testing with
nothing more than a multiplier change. And some voltage if it
needs it. Then, back off on the core, and work on your memory
a bit, and see what it can handle.

Thanks. Yes, I'd like some room to tinker around with overclocking if I
happen to gather the gumption. I'm not into "overclocking" or "system
tweaking" of voltages or timings or anything. I'm more into system
stability by running things the way they're designed to be run, and any
overclocking I don't use, in my view, becomes a system stability buffer.
It worked on my last computer. I don't want to run it just below the
point where it starts to crash or have errors, which is why it seems
sensible to me to have more than enough instead of buying just enough and
having the memory running at its maximum speed all the time it's being
accessed.

As it turns out, the 2400 Kingston memory I was looking at can only be
used in one pair on the motherboard I want. The 2133 Kingston, however,
can be stuck in all four DIMM slots. So I'll be running 2133 memory in a
2400 motherboard with an 1866 CPU. That actually sounds even better to
me.

I don't play a LOT of games, but I'm very impatient when it comes to
waiting for things to launch. So even if all I'm doing is starting my
e-mail program/newsreader, if I can shave just a second and a half off the
launch time, I'm totally elated....but not at the sacrifice of stability.
I hate crashes!

Thanks for the reply.

Damaeus

Yeah, I forgot to include that in my reply.

It's recommended to use two sticks, if you're going for the absolute
highest memory speeds. Or rather, a stick per channel. So a dual
channel motherboard, two sticks max for the high memory overclocks.

The termination schemes have been steadily improving, such that the
timing penalty of DDR3 four sticks versus two, isn't as severe as with
the previous memory standards. Still, you might find that loosening off
the timing, like make tRAS one higher, might be required with the
four sticks installed. Back in DDR400 days, going to four sticks might
have cost you one notch on clock speed (drop to DDR333 for example).

The termination scheme now is dynamic. There are termination resistors
inside the memory chips. And those are used to improve signal
quality. Previous schemes, the terminations were on the motherboard,
and the memory bus was "centered" for one particular bus loading,
and less optimal for others.

At those speeds, the command rate setting is already set to 2, so
there is no difference then between two sticks and four sticks,
as you likely needed the slackness of command rate 2, to make
those speeds work. Which leaves tCAS, tRAS, and friends, as
your remaining adjustments if the four sticks won't work right.

You should do some testing with memtest86+, to get an idea whether
it's tuned well or not. I also boot a Linux LiveCD and run the
Linux version of Prime95 (mersenne.org/freesoft), to know whether
the memory is stable enough to boot into Windows. Prime95 has a
testing feature, and you don't have to "join" GIMPS to use it.

Booting Windows is reserved for after all the memory adjusting
is finished, and to the best of your ability, the memory is
proven error free.

While AMD has traditionally supported ECC on their platforms,
it's pretty hard to find modules to take advantage of it. ECC
catches errors that otherwise might crash your computer.

Paul