4x512mb @ 200mhz: possible with E6+ rev A64/Opteron?

[duragezic]

Mobo: Epox 9NPA3 Ultra (nForce 4) w/ latest/final Aug 2006 BIOS (almost identical to the 9NPA+ minus firewire, a PCI-E x1 slot, and some accessories)
CPU: Opteron 165 rev JH9-E6
DIMMS:
1&2: 512mb PC3200 2.5-3-3-8, unknown/unmarked (bought from someone and can't be identified by any programs like CPU-Z-manufacturer info is simply blank)
3: 512mb PC3200 3-4-4-8, OCZ Value (stupid OCZ is the worst, haha)
4: 512mb PC3200 2.5-3-3-8, Corsair ValueSelect

All of my DIMMs are PC3200, and I know they are cheap or generic, but they have ran at 200mhz with < 4 DIMMs present. I also know that memory perf doesn't matter much with A64, so I don't get hardons over mem timings and frequency, but if I should be able to, I'd like them as close their rated 200 MHz as possible. I give the sticks 2.6 V, up from 2.5 V default, but even 2.7 V doesn't help.

I've read on here as well as from AT articles such as the nForce 4 Ultra Roundup that fairly recent motherboards and newer A64 chips can run 4 DIMMs @ 200mhz, even though spec'd to 166mhz. Every mobo in that roundup except the ECS ran 4 DIMMs @ exact same settings of 2 DIMMs, except at 2T of course. My 146 was a E4 rev and couldn't run 4 @ 200mhz, but from what I've read, my 165 should be able to.

Yet, it seems to refuse to run @ 200mhz. Even with my CPU at stock 200x9 and the memory speed/divider on Auto or specified as 200/400mhz DDR, it seemingly ignores that and the memory runs at 100mhz/200 DDR. I run timings all on Auto, which ends up as 3-3-3-6, 2T, Trc=7, and idle timer=16.

With my 165, the only way it will run at something other than 100mhz/200mhz DDR is to overclock the HTT and keep the memory speed as HTT * .5 (100mhz/200mhz DDR). So at my current HTT of 300, my 4 DIMMs run at 150mhz.

At HTT=300, I specified my mem speed as 133mhz, which is 300 * .66 = 198 MHz. That should work, but it refuses to POST and my mobo automatically loads the default settings after 5-10 seconds of being unable to POST.

So, my 165 runs the DIMMs the same as the 146, when in fact I've read that being a E6, it should be able to do 4 @ 200MHz. Although it is odd that with the 165, even at stock speeds and Auto or 1:1 divider, it seems to ignore that and runs at 100Mhz (the 146 would at least run them up to 166/333mhz DDR). What gives?

 

[duragezic]

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[duragezic]

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[aka1nas]

It's not likely that you will be able to run all 4 of them at PC3200 speed when you are mixing sticks like that. Too many timing variations for the memory controller to deal with.

 

[duragezic]

Really? If 3 of the 4 sticks are rated for the same speeds, couldn't I say specify them all to 2.5-3-3-8? Would that lessen the load on the memory controller at all?

 

[m1ldslide1]

My guess is your timings.

Your timings can only be as fast as the weakest link, which according to your OP is 3-4-4-8. I would be kind of surprised if you couldn't run those timings with 4x512 @ 200MHz (2T of course, like you said).

You said that you set your timings to Auto, which sets them at 3-3-3-6. Again, I think this is your problem.

 

[MarcVenice]

My mobo will set them back to ddr333 automaticaly with tighter timings. Something that did work was giving it more vramm, like 2.8 or so, whilst 2.7 is states as save by the manufacturer. It's actually holding my overclock back, I'm at 2.5ghz now, instead of 2.6ghz, with ddr 333. 4 identical sticks btw ...

 

[duragezic]

Damn. I thought that though my sticks are varied, they all have to run at the same timings (usually the slowest timings), so it wouldn't matter to the memory controller.

So, instead of using Auto timings, I set CAS-Trcd-Trcp-Tras to 3-4-4-8, which is what the slowest stick, the OCZ value, is rated for. Then I gave them 2.8 V, which was read as Vdimm = 2.88 V. Then with my HTT @ 300mhz, I set the memory to 133/266mhz DDR, which is HTT * .66 = ~198mhz memory freq. Unfortunately, computer no longer would POST. So I can't seem to run 4x512 @ 200mhz no matter what (using weakest link timings, 2.8/2.88 V)!

I guess it's possible to relax the timings even more, but I doubt that would help. I left the rest of the DRAM settings @ Auto, since I don't know each stick's rated values for the other parameters, and again they probably don't matter much.

So that kind of sucks. I know it isn't a big performance issue but I was hoping for near 200mhz, regardless of timings and 2T command rate. Still, no matter what, there is no way that I would run less than 4x512, as the RAM capacity is most important, plus with 3x512, I'd lose dual channel, and 2x512 would be dual-channel, 1T, 200mhz, decent timings, but no way those things make up for having only 1GB of RAM obviously.

Thus I am rocking out @ 150mhz freq, 2.5-3-3-6, 2T, 128-bit. I wish there was benchmarks on the performance affects of these various parameters, but I'm pretty sure it is almost nothing in real-world performance.

 

[duragezic]

MarcVenice: So yours does not run the 4 identical sticks @ DDR400? Or only will with a bit of extra voltage?

 

[aka1nas]

In theory it will auto-negotiate to the lowest common denominator, but in practice if you throw too many different sticks at it the results are usually pretty poor. You honestly won't notice the difference in anything other than SuperPi with 150Mhz DDR.