Memory sticks P4C800E-DeLuxe

B

Barend

Hi all,

Bought 4 256mb FSB-400 sticks (Twinmos dual-channel) for my new mobo,
because (if I understood Anandtech correctly) that's the best option.
But now I'm confused, because I'm reading other opinions in this ng.
Can somebody pleaser shed some light on this?

Also, I find the ide options baffling...
Got a Samsung sata hd, plus a Maxtor U-ATA, and three CD devices (one
DVD reader, one CD writer and a DVD writer).
What's the best way to connect all this?
My current A7V333 (to be abandoned for continuing probs with the VIA
chipset, IDE channels disappearing and usb likewise) took a long time
starting up in single-device RAID mode, searching for IDE devices...

BTW- This Asus looks very neat, can't wait to install my new Zalman HSF
and P4-2.8 (yeah, with heatspreader, so byebye to the Athlons).

Cheers
Barend
 
P

Philip Callan

Barend said:
Hi all,

Bought 4 256mb FSB-400 sticks (Twinmos dual-channel) for my new mobo,
because (if I understood Anandtech correctly) that's the best option.
But now I'm confused, because I'm reading other opinions in this ng.
Can somebody pleaser shed some light on this?
Click to expand...

No, running 4 sticks is not the best option.
Run 2x512MB PC3200 or PC3500 off the QVR list at asus.
the link has been posted a few times recently.

Also, I find the ide options baffling...
Got a Samsung sata hd, plus a Maxtor U-ATA, and three CD devices (one
DVD reader, one CD writer and a DVD writer).
What's the best way to connect all this?
Click to expand...

Same way i have mine + an extra hd ;)

Primary IDE- Maxtor (master)
Primary IDE- DVD-ROM (slave)
Secondary IDE-DVD-writer (master)
Secondary IDE-CDRW (slave)
Tertiary IDE (SATA) - SATA Drive
I boot from SATA drive on IDE3-Master
BTW- This Asus looks very neat, can't wait to install my new Zalman HSF
and P4-2.8 (yeah, with heatspreader, so byebye to the Athlons).
Click to expand...

Heheh, a convert! glad to hear it.
 
P

Paul

"Philip Callan" said:
No, running 4 sticks is not the best option.
Run 2x512MB PC3200 or PC3500 off the QVR list at asus.
the link has been posted a few times recently.



Same way i have mine + an extra hd ;)

Primary IDE- Maxtor (master)
Primary IDE- DVD-ROM (slave)
Secondary IDE-DVD-writer (master)
Secondary IDE-CDRW (slave)
Tertiary IDE (SATA) - SATA Drive
I boot from SATA drive on IDE3-Master


Heheh, a convert! glad to hear it.
Click to expand...

From a performance perspective, the advantage of using four sticks, is it
allows more memory banks to be used for "dynamic addressing". So, if you
bought 4 x 256 single sided DIMMs versus 2 x 512 double side DIMMs, there
would be no memory cycle performance difference. If you bought 4 x 256
double sided DIMMs, then there are twice the number of memory banks for
the memory controller to interleave. The "dynamic addressing" option is
a subtle one, and probably won't mean a big difference.

On the other side of the coin, is the electrical performance issue.
Using four double sided sticks causes less optimal signal transmission
and I think some people find they have to adjust the memory timing to
make the memory work error free. So, if your memory was rated at
2-2-2-6, maybe you end up using 2-3-3-8 or something. This is not a big
deal, because some of these memory parameters differences are hidden
by pipelining at rates of DDR400 or higher. So, relaxing the timing isn't
such a big loss.

So, a subtle gain plus a subtle loss equals ???.

I think where the biggest potential gain comes from is pure clock
speed. Sometimes, using a memory clock faster than DDR400, even if it
means relaxing the cycle timings, gives a higher overall bandwidth.
"Clock rate is king" when it comes to memory or to the processor core.

You should visit the forums of Abxzone.com and discover what the
participants there have found. After you've read a thousand posts or
so, you'll get a good idea of what brands of memory work well, and what
settings to use.

Other things you can try, are to bump up the memory voltage slightly.
Lower speed DDR is actually specified by the manufacturer to run at
2.5V. The higher performance memories are specified for 2.6V. So, your
DIMM voltage should reflect this to start with. No matter what board
you buy, sometimes even a bit more Vdimm helps (like 2.7V).

Also, be careful with any other aggressive memory settings, like Turbo,
as they may give you more negative results than you would expect.

For the Intel document on best memory configurations, see:

http://developer.intel.com/design/chipsets/applnots/252730.htm

Hmm, I just noticed on the last page of the document, that the preferred
configuration changes depending on memory speed. That doesn't affect
what I just said above, it is just mysterous - it is like one effect is
overriding another or something...

HTH,
Paul
 
P

Paul

From a performance perspective, the advantage of using four sticks, is it
allows more memory banks to be used for "dynamic addressing". So, if you
bought 4 x 256 single sided DIMMs versus 2 x 512 double side DIMMs, there
would be no memory cycle performance difference. If you bought 4 x 256
double sided DIMMs, then there are twice the number of memory banks for
the memory controller to interleave. The "dynamic addressing" option is
a subtle one, and probably won't mean a big difference.

On the other side of the coin, is the electrical performance issue.
Using four double sided sticks causes less optimal signal transmission
and I think some people find they have to adjust the memory timing to
make the memory work error free. So, if your memory was rated at
2-2-2-6, maybe you end up using 2-3-3-8 or something. This is not a big
deal, because some of these memory parameters differences are hidden
by pipelining at rates of DDR400 or higher. So, relaxing the timing isn't
such a big loss.

So, a subtle gain plus a subtle loss equals ???.

I think where the biggest potential gain comes from is pure clock
speed. Sometimes, using a memory clock faster than DDR400, even if it
means relaxing the cycle timings, gives a higher overall bandwidth.
"Clock rate is king" when it comes to memory or to the processor core.

You should visit the forums of Abxzone.com and discover what the
participants there have found. After you've read a thousand posts or
so, you'll get a good idea of what brands of memory work well, and what
settings to use.

Other things you can try, are to bump up the memory voltage slightly.
Lower speed DDR is actually specified by the manufacturer to run at
2.5V. The higher performance memories are specified for 2.6V. So, your
DIMM voltage should reflect this to start with. No matter what board
you buy, sometimes even a bit more Vdimm helps (like 2.7V).

Also, be careful with any other aggressive memory settings, like Turbo,
as they may give you more negative results than you would expect.

For the Intel document on best memory configurations, see:

http://developer.intel.com/design/chipsets/applnots/252730.htm

Hmm, I just noticed on the last page of the document, that the preferred
configuration changes depending on memory speed. That doesn't affect
what I just said above, it is just mysterous - it is like one effect is
overriding another or something...

HTH,
Paul
Click to expand...

At the risk of following up my own post...

How you assemble your system will determine what is the best approach.
Using four DIMMs _might_ make sense if you were only going to run at
stock speed, and the four kickass DIMMs you bought happen to run without
having to relax memory timing.

For maximum performance, you would want to start with a slower processor
and overclock it. For example, a 2.4GHz/FSB800 processor can be run at
FSB1000, so the core frequency becomes 3.0GHz. If you use 1:1 as the
CPU to memory ratio, the memory required is PC4000 or DDR500. It is
likely that only two sticks of PC4000 can be run at full speed while
doing this kind of overclock. I would expect the memory performance
running this way, to exceed a 3.0GHz/FSB800 plus PC3200/DDR400 memory
combination.

If, on the other hand, you want to put as much memory as possible in
the machine, then the compromise is that you cannot run the memory
flat out. There has to be some compromises if you really need as
much memory as possible. Running the memory bus close to stock speed
makes a full memory configuration more likely to work, at the expense
of slightly less bandwidth.

Just in case I left the impression that 4 x 256 was generally a good
thing :)

HTH,
Paul
 
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