SLI performance hit and screen corruption

[Rukee]

Just picked up the ASUS A8N SLI Deluxe MB and a pair of ASUS 6800 NU cards.
But running in SLI the system is slower then running just one card...also the screen is corrupted durring benching with lines going acrost the screen left to right, mostly in the upper part of the screen, but the text at the bottom of the screen is goofy as well, like some of the pixils are moved around.
Single card with no OC scores a 19,200 in Futuremark 2001se, the other by itself scores a 18,980 nether of them shows any corruption alone. The two together in SLI score a 18,880.
I have tryed Auto and SLI in the BIOS, SLI is enabled in windows...do I have a bad pair of cards? Bad MB? what the heck is going on??

[DoGMaN]

I know this is probably a dumb question, but did you flip the stupid SLI selector card over to dual card? You also can only use the 66.93 drivers from what I have seen so far, but I gather from your post that you already have them.

[Spoo]

Have you tried 3dmark03 and 05? I don't think SLI gives you much extra performance in 01.

[Rukee]

I have whatever drivers were at nvidea`s site...running the timedemo1 in UT I get 155fps in SLI and after about 8 passes the fps fall off by about 10fps to 145fps.
Running a single card I get 165fps and it stays there pass after pass.

[DoGMaN]

I ran 3dmark2k1 on my machine and I'm getting about 17000 with 2 6600GTs. In 03 I get 14700 so 01 is not a good gauge. I don't have old UT but it sounds like a driver problem. Try enabling the load balancing meter see if only one card is doing the work.

[Rukee]

When I enable the load balance meter, they appear to be about the same, however, the screen corruption seems to be worse when it`s enabled.
It does score alot higher in 03 with SLI, dnlding 05 now.

[DoGMaN]

Did you fully uninstall the old nforce chipset (especially the AGP) drivers before throwing in the new board? I originally had some issues simply because I hadn't removed them.

[Rukee]

this is a fresh reformat with just the XP pro, VIA 4-in-1s, RAID, directX, and VC drivers installed.

[DoGMaN]

this is a fresh reformat with just the XP pro, VIA 4-in-1s, RAID, directX, and VC drivers installed.

Typo???

You'll need to use the Nforce4 drivers off the CD or the ones that you can download off of MSI. The ones at nvidia.com (5.10) don't work right with nf4. I think the newest ones are 6.34

[Rukee]

Yes, I did load the NF4 off the CD, sorry.
The perfromance hit appears to be in directx8 based stuff.
03 and 05 both show good improvments with sli.
single card:
03 = 8956
05 = 3675
two cards:
03 = 14305
05 = 6654
I should have done more testing, however, the screen corruption is still bad with the lines dancing acrost the screen.

[Rukee]

hmmm...I only see the corruption in futuremark, aquamark looks fine.

[Rukee]

I`ve managed 8053 marks in 05 by OCing the cards from 325 stock to 440, first by the auto detect, then upped in a few times from there, and the memory up to 762. Seems like some good clock speeds starting out for cards that are less then half the price of the ultra cards.
I`ll try to OC the a3200 later after I get the VCs working good.

[Ulti]

hmmm...I only see the corruption in futuremark, aquamark looks fine.

And gaming? (That's what it's all about right )

[compfreakz]

8053 3DMarks 05 is a very nice score

[Rukee]

Wow, I just ran a 17,3xx in 03, but I can`t publish the results, it says I have a generic vga chipset.

[mrlobber]

Wow, I just ran a 17,3xx in 03, but I can`t publish the results, it says I have a generic vga chipset.

Generic... sure

So the dx9 stuff runs just fine?

[Rukee]

Yeah, it sure does. I got 05 up to 8257.

[STEvil]

what power supply? are they each on their own cable so they arent fighting for current?

[Blindbat]

hey Rukee, we seem to criss cross between here and vapochill forum.

maybe this will help a little, glorfy from the site I hang around has a similar set up as yours, no phase...., but 6800 Gt's you might want to read/breeze through it..last I know he was in the

3DMark03 =
21411 , and being stupid, I left the memory on the GC at stock - not 1140!

3DMark05 = 9889 , disappointed not to get 10000!

http://www.bleedinedge.com/forum/sho...1&page=1&pp=15

[fagin]

hey Rukee, we seem to criss cross between here and vapochill forum.

maybe this will help a little, glorfy from the site I hang around has a similar set up as yours, no phase...., but 6800 Gt's you might want to read/breeze through it..last I know he was in the



http://www.bleedinedge.com/forum/sho...1&page=1&pp=15

Hehe - Glorfy's set up = broken!, both cards work, but not in SLI mode Instantly crashes when second card enabled. Oh dear!

[Blindbat]

Hehe - Glorfy's set up = broken!, both cards work, but not in SLI mode Instantly crashes when second card enabled. Oh dear!

U got to be joking ! Darn sorry to hear that g.....

[Rukee]

what power supply? are they each on their own cable so they arent fighting for current?

The cards don`t have power connecters on them, instead the MB has a single molex connecter next to the first card.
I`m only benching with a a3200 too. :o

Someone on another forums pointed me to this. 3rd paragraph down...Looks like I`m not the only one with 6800nu SLI trouble.

[DoGMaN]

Man that is too bad. I wonder if maybe the cards draw to mcuh power (combined) from the PCIe slots. I haven't seen any artifacting on my system, but I have lowly 660GTs

[LardArse]

Hmm not getting enough power?
But on mine, SLI mode does eat up CPU power seemingly, my GT1 for 03 is more than 10fps slower than with a single.

[fagin]

Several things here.

1) The PCIe slots and the MB molex connector supply enough power to run my 6800GTs at 350/1000 - no more. I have to connect the extra power for more.

2) PCMark 04 loses 10% for me with SLI enabled, which would back up what Lar.dArse says about Gt1.

3) I had exactly the same screen disruption that others are repporting - and it just disapeared - I have no clue why!

4) My cards now do not work in SLI mode - again I do not know why! I have tried everything I can think of including reinstalling windows. Heres what happens:

I run fine with one card (either card in the main slot) as soon as I try to boot into windows with the second card I will get a BSOD before the welcome screen (have now reverted to SP1 to make sure there is no issue with NX). If I disable the second card in safe mode, and boot into windows, the screen will instantly blank, no BSOD no warning no freezing - blank. If I leave the drivers uninstalled I boot into windows. On installing the drivers, It installs the fiirst one fine, starts the second one and the screen will freeze. This is with ANY drivers. I'm at my wits end!

Still at least it rocks when it does work