nForce2 dual-channel report

[Chalnoth]

Just in case anybody's interested!

Well, now that I got my bad stick of RAM replaced today, I decided to do a few benchmarks to see the difference between single-channel and dual-channel on my system. Unfortunately, I couldn't help but have different memory sizes, but it turns out that this didn't seem to matter much in the tests I did.

System:
Asus A7N8X
Athlon XP 2000+
256MB/512MB of RAM
Gainward GeForce4 Ti 4200

Results:

(benchmark): (single-channel) / (dual-channel)
SiSoft Sandra:
Dhrystone: 4313 / 4539 (MIPS)
Whetstone: 2236 / 2284 (MFLOPS)
Integer aEMMX/aSSE: 8615 / 9060 (it/s)
Floating-point aSSE: 9972 / 10035 (it/s)
Int Memory Bandwidth: 1841 / 1931 (MB/s)
Float Memory Bandwidth: 1792 / 1810 (MB/s)

Unreal Tournament 2003 (Suntemple demo):
Settings: 800x600x32, 2x FSAA, 8-degree anisotropic
Botmatch: 40.6 / 37.8 (fps)
Flyby: 70.5 / 70.6 (fps)

3Dmark2001 (default benchmark):
10123 / 10349

My conclusions:

While the SiSoft results show some improvement, UT and 3DMark don't. While I've repeatedly stated that I don't like 3DMark2001, I do feel that it's not a bad benchmark for doing a few things. I do feel it is decent for checking reasonable system performance tweaks, though all benchmarkers really must be aware of how much the 3DMark2001 results can vary. The results I gave above really don't vary much more than the random variation between tests, which means that there is essentially no difference in this benchmark. As for the UT2k3 benchmark that went down, well, the demo was obviously different between the two tests, so it too can be thrown out.

So, overall, I'd just say that there isn't a compelling reason to believe that one must utilize a dual-channel configuration with the nForce2. If building a new system, I would personally recommend purchasing one large stick of RAM with an nForce2 instead of two smaller sticks, as the "companion" stick can be purchased later when the memory is needed.

[demonized]

thx for sharing your test results.
Ill keep those things in mind.

[Cotita]

I agree to some extent.

Thing is that XP likes lots of ram. People prefered a 512mb stick instead of 2x256 because on VIA motherboards, specially KT333/KT400, they had lower performance or stability issues when using fast timings.

With the nforce2 its quite the contrary, it has better performance with 2 sticks than just one. Judging by your results it seems that the nforce2 likes same size sticks better, and even more so when running at synchronous 166mhz system bus.

512mb sticks cost almost the same or in some cases a little higher than 2x256 sticks, so if you start with say a 256 stick, you will see a nice performance boost when upgrading to 512.

I'm looking forward to get an Asus A7N8X myself so I hope to hear more about your experience with it.

[anxdiety]

Well in my nforce 2 i just used a single stick of 512 and hope to pair it off someday for some dual channel goodness. Nothing better than getting a higher boost than normal when you add something extra to the system. Maybe by the time i drop in the extra 512 amd can have the barton chips out to pair it up with and take more advantage of the memory throughput

[lagadu]

you might not be using the extra bandwith for now, but it's there, in case you ever upgrade to a 200mhz fsb barton or something, the extra bandwidth it uses is avaliable without having need to upgrade the mem/mobo, plus nvidia chipsets are the best in both performance and stability for amd, even without considering dual-channel.

[Chalnoth]

Originally posted by Cotita
I'm looking forward to get an Asus A7N8X myself so I hope to hear more about your experience with it.

So far, my experience has been great. Once I got my bad stick of RAM replaced (Crucial PC2100..they replaced the defective stick very quickly, so I'll definitely buy directly from Crucial again...), all I had to do was set the memory timings to "aggressive" and go. Not a crash since.

There are only two outstanding issues right now, and those are with regards to Linux. There is no native sound driver support, so while I do get sound, I don't get any of the advanced or accelerated sound of the nForce2. The second is that nVidia provides no agpgart driver for the nForce2, except in nVidia's own graphics drivers. This means that I have been unable to get the nForce2 to work properly with a Radeon 9700 Pro under Linux. It works great with a GeForce4 Ti 4200. nVidia really needs to improve their Linux support! Hopefully now that the nForce2 is apparently going to sell a whole lot more than the original nForce did, we'll see more Linux support...

[Cotita]

by the way do you have the normal or deluxe version?

I've heard that the normal version can't use the nforce2 nvidia drivers but only the ones that come on the cd. Although there seems to be a workaround on this.

[SavagePaladin]

I'd like to say latency dropped quite a bit when I added a second stick, on non game stuff. I can't quite attribute it to a simple RAM increase quite yet.

[Chalnoth]

Originally posted by Cotita
by the way do you have the normal or deluxe version?

I've heard that the normal version can't use the nforce2 nvidia drivers but only the ones that come on the cd. Although there seems to be a workaround on this.

I think I have the highest-end version (It includes all the optional junk, like the serial ATA and whatnot). The nVidia drivers (both Linux and Windows) seem to work fine.

[pelly]

As far as I know...the only issues regarding the use of NVIDIA's 2.0 nForce drivers are dealing with the APU. Here, those boards using CMedia chipsets cannot use the NVIDIA driver for the MCP-T's APU. Aside from that, everyone is encouraged to use NVIDIA's drivers for the most up to date solution...

:D

[SavagePaladin]

Say Chalnoth...when I was bugging NV about linux support, they said the problem involved few OEMS or system integrators asking for it. (One apparently did, but backed off on finding out they'd be doing their own tech support.)

[Chalnoth]

Originally posted by SavagePaladin
Say Chalnoth...when I was bugging NV about linux support, they said the problem involved few OEMS or system integrators asking for it. (One apparently did, but backed off on finding out they'd be doing their own tech support.)

Well, as I said, this should change before too long as the nForce2 looks like it's going to be significantly higher-volume than the original nForce was, and nVidia has more parts in the pipeline that may do even better (If nVidia follows the same pattern they did for video, I see no reason why nVidia will not become the #1 player in the AMD chipset market over time...cracking the Intel market will be tough, though, even if they do get a license later on).

[lothodon]

the dual channel won't really show any major improvements until the integrated graphics motherboards are out. from what i've read, that's were the dual channel improvements will come from.

[Blakhart]

http://www.nforcershq.com/forum/index.php
for more nforce goodness.
From what I see, the dual channel gives abt %5 increase in performance, memwise, if the dual sticks are the same, and not dropped into what is termed super stability mode. This mode is regardless of the timings indicated. It is slowest of all timings and is usualy caused by non identical brand or type mem, or speed diffs and so on. This may be at work in your case.

[Chalnoth]

I don't think so. They're both sticks of Crucial PC2100 CAS2.5 DDR, with memory timings set to aggressive.

And where on those forums are you looking? With a fairly quick look, I don't see anybody reporting single/dual-channel DDR performance.

[Blakhart]

Sorry, just a pointer to get you to the forum.

[Dazz]

Does anyone know if Dual channel works with say 128MB & 256MB DIMM's? or does it have to be the same like 256+256MB?

[Blakhart]

I think so, and you must place them in the right slots, as two slots are on the same bank. Check your manual for details on this, or ask at the forum I url'd. Your mobo needs to support dual channel in the first place, as some do not, these usualy being the cheapest. What model is yours?

[Dazz]

I havn't got one just yet but am looking into replacing my 2+ year old A7M266 :) I think both models support dual DDR just the deluxe has alot more items like Soundstorm SATA etc. I havn't yet decided on which to get depending on the price but what i am looking for is if i should get rid of my Audigy and use the Sound Storm APU?

[Blakhart]

I say save up for the D model, forget add in sound.

[Chalnoth]

Originally posted by Dazz
Does anyone know if Dual channel works with say 128MB & 256MB DIMM's? or does it have to be the same like 256+256MB?

While I don't have the memory to check, it does appear that the nForce2 will support memory in any configuration, but it will only have optimal performance if there is the same amount of memory in both banks.

Currently I'm not sure exactly how flexible this is. But, if you had one 256MB and one 128MB stick, I see two possibilities:

1. Data will be striped across the two banks with twice the stripe size in the 256MB stick, resulting in an effective 96-bit memory bus width (as opposed to 128-bit with two identical DIMMS).

2. The memory controller will configure the striping as to give full performance for the first 256MB of memory used, and only 64-bit performance for the last 128MB of memory.

Anyway, I really can't be absolutely sure right now what would happen, as I can't test it. However, my Asus A7N8X manual implies that there will still be some performance improvement, even if the sticks aren't identical in size.

Btw, the thing I'm most curious about right now is whether you can get optimal performance with 1x512MB in one bank and 2x256MB in the other bank. It is theoretically possible...it just depends on how flexible nVidia made the memory controller.

[Dazz]

So it's not like Intel's or SIS P4 chipsets where they need to be exactly same or they won't work so falls back to 64bit mode.

[Blakhart]

You might want to check out nvid's white papers on their mobo.

[Chalnoth]

Yes, nVidia's docs state that the memory controllers will still allow some benefit from different-sized DIMMs.

[StealthHawk]

Originally posted by Dazz
I havn't got one just yet but am looking into replacing my 2+ year old A7M266 :) I think both models support dual DDR just the deluxe has alot more items like Soundstorm SATA etc. I havn't yet decided on which to get depending on the price but what i am looking for is if i should get rid of my Audigy and use the Sound Storm APU?

nforce2 has better sound than the original Audigy. of course it doesn't support EAX3, but not many games do yet.

http://firingsquad.gamers.com/hardware/audigy2_versus_nforce2/default.asp

Firing Squad ranks the Audigy2 as having better sound though.