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piper1
07-15-05, 08:13 PM
I just put the finishing touches on my new SLi system, but I'm having some difficulties with Doom 3. Specifically, the game will not run in SLi mode - it simply appears to ignore the second GPU. I have the load balancer running, but it shows no activity - just two empty columns in conjunction with the horizontal line splitting the screen. I run 3DMark03/05 as well as Republic Commando and the load balancer works just fine - filling both columns almost entirely. I've run the timedemo for Doom 3 with SLi enabled/disabled, and the frame rate results are identical. I've reinstalled the drivers and switched the cards around, but no luck. Any ideas?

A8N-SLi Premium
2x 7800GTX
1gig Corsair TwinX
San Diego Athlon 64 3700+

3dmark2005: 9760
3dmark2003: 26951

OWA
07-15-05, 10:17 PM
That's what I get as well and get around 84fps in the regular timedemo.

On a slightly different note, I'm not totally sure how to read the load balancer. Does the horizontal line show how the load is being split betweeen the two cards and I guess the columns show the actual load on the particular card. Is that correct?

piper1
07-15-05, 10:46 PM
I believe the line represents which SLi mode the game is in. And my understanding of the columns is the same as yours. I just think there's something fishy with Doom 3 as my framerate is nowhere near what some of the reviews on SLi systems are reporting. My Timedemo reports out around 106 fps @ 1280x1024. Again, this framerate is identical between SLi/Non-SLi timedemos.

OWA
07-15-05, 10:50 PM
It definitely doesn't move or do anything like many of the other games. Maybe you should try nHancer and change the SLI settings to a different mode to see if anything changes.

OWA
07-15-05, 10:56 PM
Actually, I think it's working for me. I'm running at 1600x1200 4xAA/8xAF and get like 80+ when using SLI and only get 50+ when using a single card.

thanosAIAS
07-16-05, 03:43 AM
Same here. It happens with other games too. What's going on?

ricercar
07-16-05, 05:04 AM
Have you enabled two cards in your BIOS?

In addition to the Display control panel SLI enabling option, there's a BIOS setting on my A8N SLI Premium to enable one or two video cards (one/two/auto). Without this, the primary card gets 16 PCI Express lanes, and the second card gets only 1 PCI Express lane, so one cannot enable SLI regardless of the driver setting.

I set my BIOS option from auto to two to ensure good things would happen, and they do.

Zurble
07-16-05, 06:53 AM
It's bacause it works in static SFR, there is no load balancing.

if you have 80fps in 1600 4xAA 16xAF in default timedemo, no worry to have.

often reviewers use theire own timedemos, check again

but 3dmark2005 seems low to me...u should get at least 10500 non overclocked and 11500 with some overclocking
3dmark2003 seems more correct

OWA
07-16-05, 08:52 AM
It's bacause it works in static SFR, there is no load balancing.
Ah, thanks for the explanation.

Zurble
07-16-05, 09:01 AM
i am checking right now, because it is set to 1 in nvapps.xml which means AFR, then we should see the green bars

perhaps something to do with opengl

OWA
07-16-05, 09:23 AM
When I switched Star Trek Elite Force 2 (also opengl) to AFR it acts the same as Doom 3. I get the line in the middle and the vertical columns are empty. It didn't run well in AFR mode but it acts the same as Doom 3 as far as the load balancing anyway.

thanosAIAS
07-16-05, 09:28 AM
Both 3dmark and doom3 are AFR. (vertical bar should vary, and horrizontal should stay in the middle). The thing is the vertical bar doesn't vary within the game.

Zurble
07-16-05, 09:31 AM
Codecreature and flatout are AFR too but directx ones, and the bars are working there...
startrek is opengl if i remember

i found this:
http://www.ocmodshop.com/current_sli/big/a.jpg
6600 GT SLI

wierd, that would mean the GPU is not working a lot...in DOOM3 !!! knowing that you gain a lot with SLI, i doubt about that...

Zurble
07-16-05, 09:50 AM
by the way, 106 is probably CPU limit, thus u'll see no difference between SLI/non SLI
try bumping 1600 ULTRA 4XAA with TAA 16XAF, and try both again, u ll see the difference (i think that without ULTRA the difference is still low)

16X -> image_anisotropy in console
TAA is in control panel
ULTRA and 4xAA in option/system

edit: correction, u should see a difference without ULTRA too

piper1
07-16-05, 12:43 PM
Unfortunately my current LCD only goes to 1280x1024. I have tried all the settings maxed-out at this resolution as well. I've set them within the Performance Settings of the NVIDIA control panel as well as the Advanced Settings within Doom 3. Still no impact to the Load Balancer. I did notice something strange, though. The demo runs smoothly and reports 95fps at these settings; however, when I try to actually play the game with the same settings it's entirely unplayable - hovers in the 15-25fps area. Does the demo ignore all settings but the resolution?

I ran 3Dmark2005 again this time it gives a score of 10734 with all defaults enabled.

ricercar
07-16-05, 01:06 PM
I've run the timedemo for Doom 3 with SLi enabled/disabled, and the frame rate results are identical. I've reinstalled the drivers and switched the cards around, but no luck. Any ideas?
Sorry to report that a consistent <Timedemo = 84 FPS> appears to occur when a NV4x video system is power-starved. It may be time to upgrade your PSU.

Peaking at 84 FPS reminded me of my Timedemo before I had a SLI-capable PSU. I re-tested my A8N SLI Premium + 6800Ux2 system:
- with one GPU & with SLI
- with & without a PCI Express power connector attached
- on 250, 350, & 510 Watt PSUs.

When a NV4x video subsystem is starved for PSU power, either from lack of PSU wattage or lack of PCI-Express power connector, I observed mid 80s FPS in Doom3. This was true for SLI or single, regardless of the driver or Doom3 settings.

84 FPS is apparently the low-power throttle-back point within the drivers.

OWA
07-16-05, 01:25 PM
Hmm...

single card, 1600x1200 4xAA/8xAF, 54 fps
SLI, 1600x1200 4xAA/8xAF, 84 fps

single card, 1280x1024 4xAA/8xAF 74.5 fps
SLI, 1280x1024 4xAA/8xAF, 90 fps

single card, 640x480 4xAA/8xAF 93.8
SLI, 640x480 4xAA/8xAF 92.2

I guess I expected a much bigger jump than just 6fps at 1280x1024.

piper1
07-16-05, 01:49 PM
It seems strange that this would be the case for me as I have a ENERMAX EG565P-VE FMA2.0 SLI ATX12V 535W (http://www.maxpoint.com/home/products/pow_supp/spec_pg/whisper2_2_0/index.htm)Power Supply. However, I am having a few issues that may suggest the power supply isn't working correctly. First, this power supply has two dedicated 6-pin connectors for the SLi system; however, when I use them the warring "that my video cards are not getting enough power and have been clocked-back to preserve stable operation" appears. I have to use the power adapters supplied with the video cards to circumvent this error. Second, I can initially overclock the cards, but if the system has been running for some time and I try to adjust the clocks again it will always fail the "verify clock" test. It wont even let me set it back to the default 450/1200!!

How about some suggestions for "reliable" SLi power supplies?

OWA
07-16-05, 02:26 PM
Did you provide power to the ASUS EZPlug?

I'm also having some stability issues and I'm using an Enermax power supply that is on the SLI approved list. I think that will be the next thing I try though (getting another power supply).

Also, from what I can tell, the load balancing doesn't change or anything in OpenGL games when AFR is used (like someone mentioned already). Every game I've tried that is OpenGL, the line just sits in the middle and the vertical columns are empty (I've tried COD, COR, D3, D3 RoE, NASCAR Racing 2003 -- in opengl mode). I used SFR with NASCAR 2003 and the load balancing moved around, etc. In D3D games that use AFR, it also moves around.

Since you have an ASUS A8N-SLI Premium also, can you check to see how hot the chipset is getting? If I put my finger on the ASUS Fanless Design plate, it's basically too hot to keep my finger on it. I'm wondering if that could be the source of my problems. The temps on everything else in the case seem pretty good.

piper1
07-16-05, 03:24 PM
Yep, the EZplug is attached. Also, I ran Doom 3 for about 30 minutes and the plate/pipe on the chipset are barely warm to the touch.

Zurble
07-16-05, 04:20 PM
Sorry to report that a consistent <Timedemo = 84 FPS> appears to occur when a NV4x video system is power-starved. It may be time to upgrade your PSU.

Peaking at 84 FPS reminded me of my Timedemo before I had a SLI-capable PSU. I re-tested my A8N SLI Premium + 6800Ux2 system:
- with one GPU & with SLI
- with & without a PCI Express power connector attached
- on 250, 350, & 510 Watt PSUs.

When a NV4x video subsystem is starved for PSU power, either from lack of PSU wattage or lack of PCI-Express power connector, I observed mid 80s FPS in Doom3. This was true for SLI or single, regardless of the driver or Doom3 settings.

84 FPS is apparently the low-power throttle-back point within the drivers.

these are normal scores and peaking at 85 FPS in 1600 full detail full options is normal, don't worry.
i had a single card before plugging my second card and single card scores were the same as with 2 card and SLI disabled, there is no POWER issue on an OCZ 520 (peak 620W)

running at 640 in single card mode shows you what is the CPU limit....there is no way you can go above with SLI or whatever supercard GFX you have.
That's why you won't notice any difference in 1280 between SLI and single card. because 1 card is far enought at that resolution, your CPU is not.

an other trick to convice you is to try rivatuner and check mem/core speeds.....they are not "throtlle" speeds

Zurble
07-16-05, 04:27 PM
It seems strange that this would be the case for me as I have a ENERMAX EG565P-VE FMA2.0 SLI ATX12V 535W (http://www.maxpoint.com/home/products/pow_supp/spec_pg/whisper2_2_0/index.htm)Power Supply. However, I am having a few issues that may suggest the power supply isn't working correctly. First, this power supply has two dedicated 6-pin connectors for the SLi system; however, when I use them the warring "that my video cards are not getting enough power and have been clocked-back to preserve stable operation" appears. I have to use the power adapters supplied with the video cards to circumvent this error. Second, I can initially overclock the cards, but if the system has been running for some time and I try to adjust the clocks again it will always fail the "verify clock" test. It wont even let me set it back to the default 450/1200!!

How about some suggestions for "reliable" SLi power supplies?

i have the same issue (no overclock/downclock possible) as you but at as nothing to do with heat or power...it happens when u start any D3D/Opengl game even for a few minutes), a simple reboot correct the issue even if your system still powered/heated the same

Zurble
07-16-05, 04:29 PM
Hmm...

single card, 1600x1200 4xAA/8xAF, 54 fps
SLI, 1600x1200 4xAA/8xAF, 84 fps

single card, 1280x1024 4xAA/8xAF 74.5 fps
SLI, 1280x1024 4xAA/8xAF, 90 fps

single card, 640x480 4xAA/8xAF 93.8
SLI, 640x480 4xAA/8xAF 92.2

I guess I expected a much bigger jump than just 6fps at 1280x1024.

you can't, your CPU is guilty, more GPU power won't help as 1 of your 7800 is already far enought at that res

Amuro
09-15-05, 12:27 AM
Doom 3 is weird. Sometimes it ignores the second GPU.

I installed Doom 3 the other day to run the time demo. The first time I ran it with SLI @1280x1024 high quality with 4xaa and 8xaf, I got a score of 104.3, worked fine. Then disabled SLI and got a score of 77 on single card, also fine. Then I re-anable SLI and got a score of 59 with same setting. Exited the game, swtiched rendering mode from auto-select to AFR, and ran it again, and this time I got 104 again. I thought it was the rendering mode. But it wasn't. Today, I got the same 59 score with AFR, or any other mode. After reboot, I got the correct score again, which is 104. Also, setting the SLI config in BIOS to dual card or auto makes no difference. It seems to be random.