• Competitor rules

    Please remember that any mention of competitors, hinting at competitors or offering to provide details of competitors will result in an account suspension. The full rules can be found under the 'Terms and Rules' link in the bottom right corner of your screen. Just don't mention competitors in any way, shape or form and you'll be OK.

8800GTS SLI woes

Crowze

Crowze

Crowze

Associate
Joined
13 Mar 2007
Posts
1,310
Location
OcUK
Before having a bit of a rant, here's my rig:

Asus A8N32-SLI Deluxe
Opteron 185 @ 3GHz
2GB Corsair DDR400
2x Inno3D 8800GTS 640MB @ 650/1050
Thermaltake Toughpower 750W
XP Pro SP2 (32bit)

I've been running this pair of cards for a while now using the latest beta drivers, and having just run through the Crysis and UT3 benchmarks it seems that running them in SLI is in fact slower than a single card, despite what 3DMark06 reckons. I also noticed that they both seemed more jerky, and I'm assuming this is caused by having to stream the data to both GPUs - I've noticed similar behaviour in TDU as well. This leads me to believe that it's severely CPU-bound, but before jumping to conclusions I thought I'd ask for advice as to anything I may have overlooked that could cause this.

If it is the case that my CPU isn't up to it then I'm left with two options. First is to sell one of the GTSes, which I'm a little loath to do because of the huge loss I'd make on it. Second is to buy new motherboard, CPU and memory, which for a half-decent SLI setup is far from inexpensive and I'm a little apprehensive about the gains I'd see from doing this. Does anyone here have a similar setup but with a newer CPU, such as a Q6600 - if so can you let me know how it fares in some benchmarks, and whether you see any similar jerky behaviour?

Cheers :).
 
Not sure about UT3, but are you running the full version or crysis or the demo? Reason i ask is the demo dosent support SLI
 
SLI works in the crysis demo - I believe the latest patch for the fullgame makes far more effective use of SLI tho.

You are CPU limited by that setup but I wouldn't think that was just your problem.
 
Perhaps you could try changing the rendering mode?

ive had a couple of odd problems with SLI.. like in COD4 one of my teammates disappeared if i turned a certain way and look back, then a blank screen on reboot until i reboot again.

I dont think ALT tabbing out of games is a good idea with SLI either.

Games shouldnt be jerky even with that CPU, mine is at stock and the cards are still noticeably faster than my old GTX.
 
I've not ran SLI or crossfire before so I can't comment on that but I do want to ask what resolution do you game at?. The higher the resolution the less your CPU gets worked so at 1600x1200 and above I couldn't see your CPU being a bottleneck.
 
Thanks for the feedback.

MeatLoaf, I'm using the full version.

Perfect_Chaos, good suggestion but I've already tried changing it in nHancer. For Crysis the default is fastest, old AFR a few fps slower, and SFR is rubbish i.e. < 10fps.

J.D., 1680x1050. I know that even at that it's CPU limited, but I wouldn't have thought it to be so bad as to actually reduce performance in SLI.

I'm beginning to think it may a motherboard issue then. I've just tried a single card in each slot, and it the bottom one it works as expected but when in the top Windows does some strange things... it shows up fine in the device manager but sets the resolution to 640x640x4bit and won't let me change it, nor will it open the nVidia control panel. Any ideas?
 
Well if you want to rule your motherboard out then feel free to bring your cards here and we can try them in my machine in sig :)
 
Last edited:
Thanks for the offer Meaty but I already have a spare cheapo SLI board, currently being used as a MythTV box :). Tested the cards on there and they do pretty much the same thing, which I guess isn't surprising. What is strange is that a 7300GT works perfectly in the top slot on the A8N whereas the 8800 does the fixed low-res thing... I'm reinstalling the nVidia drivers now to see if it helps at all.

Edit: New drivers did help but I'm back to the old problem. However, I've just run the Crysis bench having taken the SLI bridge off, and it made no difference at all. May be on to something here...

Edit 2: Yep, SLI bridge does nothing at all. Time to scour the bay for one the right size.
 
Last edited:
Crowze said:
Thanks for the offer Meaty but I already have a spare cheapo SLI board, currently being used as a MythTV box :). Tested the cards on there and they do pretty much the same thing, which I guess isn't surprising. What is strange is that a 7300GT works perfectly in the top slot on the A8N whereas the 8800 does the fixed low-res thing... I'm reinstalling the nVidia drivers now to see if it helps at all.

Edit: New drivers did help but I'm back to the old problem. However, I've just run the Crysis bench having taken the SLI bridge off, and it made no difference at all. May be on to something here...

Edit 2: Yep, SLI bridge does nothing at all. Time to scour the bay for one the right size.
Click to expand...


Ive got a spare asus flexi bridge here you can have mate for nowt.

EDIT : Not sure but are you having any of these issues?

http://forums.overclockers.co.uk/showthread.php?t=17843595&highlight=startername_MeatLoaf
 
Thanks for the offer, I think I'll hold fire for the moment though as there's still some other things to think about. I've taken a multimeter to the bridge and there are no broken connections, and I did use a different bridge when testing the cards on the other mobo, so I don't think that's the cause. I'll try out a few other things, have a think and let you know how it goes.

Edit: Found a handy little thing called the SLI load balance graph, which has practically answered all my questions. Firstly, SLI is working fine. Second, at stock settings, it's hardly being used at all and is CPU-limited, but with AA and AF cranked up it uses both GPUs to very good effect. Thanks for the help all :).

500th post as well... yay :).
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom