Help with SLI

[Slughammer]

I made my first amd computer last December and just got it up and running about 4 months ago. I made it so I could utilize SLI technology. I have the AOpen Aeolus 7800 GTX DVD256MB NVIDIA card. I have the LanPartyUT nf4SLI-DR mobo. I just bought GEFORCE 7800 GT 256 video card to run in SLI mode.

When I go to control panel-display-GeForce 7800GTX page and hit SLi, it says"You must remove any graphics cards that are not compatible with NVIDIA SLI technology before you can enable SLI. It does NOT give me the option to enable it. I only have these two video cards installed and this was a new system prior to that.

Any help would be greatly appreciated.

Thanks,

Matt

 

[tehrobzorz]

have you ever thought why they say ' the same card'

have you noticed that youve got a gtx and gt?

just MAYBE 0.o they arnt the same chip? ( g70 etc.. )



or maybe im jus really shit.. ask around for jumping jack he will solve eveything

 

[Mousemonkey]

You have 1 GTX and 1 GT correct?, if so you need to change one to match the other, I tried something similar last week with a GT and a GTO and found that they will not Sli, orrrr you could try flashing the BIOS on one of the cards to match the other but if you get it wrong you could end up with a dead card.

 

[Mousemonkey]

They are the same GPU dude, but the Bios is different I think.


http://tomshardware.co.uk/2006/10/04/nvidia_tightens_up_midrange_performance_uk/page2.html

 

[Dahak]

Unfortunately to run SLI both cards need to have the same bios version.As long as the bios is the same no prob.I have a 7800gt and a 7800gt co.Both are from evga and both contain the same bios,just the co model has a copper heatsink and is clocked slightly faster than the gt.Otherwise they are identical cards.And if you want to run with the faster speeds,just put the faster card in slot 1 and the slower one in slot 2.The second card seems to run at the first cards speeds.But ya in your case I would make sure both cards have the same bios.Flash them both to the newest bios version.That should take care of the problem.Goodluck.

Dahak

AMD X2-4400+@2.4 S-939
EVGA NF4 SLI MB
2X7800GT IN SLI
2X1GIG DDR IN DC MODE
WD300GIG HD
EXTREME 19IN.MONITOR 1280X1024
ACE 520WATT PSU
COOLERMASTER MINI R120

 

[prozac26]

Will not work.

Need same GPU.

However, the 7800GT has only 20 pipelines, and none can be unlocked.

Flash them both to the newest bios version

Interesting, but I highly doubt it'll work.

Why?
Well, the 7800GT is a "crippled" 7800GTX, but, there's no way to unlock pipelines on it, so flashing BIOS will ruin it. Same with the 7800GTX, wrong BIOS will ruin it. I wouldn't touch the video card BIOS.

I will suggest returning the 7800GT, and getting a 7800GTX, or just sticking to one.

 

[darkstar782]

Unfortunately to run SLI both cards need to have the same bios version.As long as the bios is the same no prob.I have a 7800gt and a 7800gt co.Both are from evga and both contain the same bios,just the co model has a copper heatsink and is clocked slightly faster than the gt.Otherwise they are identical cards.And if you want to run with the faster speeds,just put the faster card in slot 1 and the slower one in slot 2.The second card seems to run at the first cards speeds.But ya in your case I would make sure both cards have the same bios.Flash them both to the newest bios version.That should take care of the problem.Goodluck.

Lies.

Early SLi drivers required identical BIOS versions. This is *not* the case now.

Use nBiToR and nvFlash to edit the 7800GTX bios to present itself to windows as a 7800GT. This will not lock any of its pipelines or stop it working, but as soon as you put it into SLi (if it works) the extra pipelines will more than likely stop working. All you are doing is changing a couple of Bytes that the card reports itself to windows with.

Because one card is 20 pipes and one is 24, it may or may not work. A 7900GT and a 7950GT for example would work fine with this method.

It doesnt really matter which card is in which slot while in SLi mode, the faster card always slows and masks RAM to be the same as the slower card. I would however have the 7800GTX in the main slot just because then in non-SLi mode you are using the faster card.

To be honest if you have the option to return the 7800GT still you should do that. This is not an ideal SLi setup.

 

[Mousemonkey]

Dude the 7800GT and the 7800GTX are the same GPU the G70, I'm pretty sure it's a BIOS thing that won't let them Sli but I would'nt f**k with the BIOS 'cos I'm not that brave/stupid. :lol:

 

[darkstar782]

Hehe BIOSes can be usefull, the 5900XTs modded into 5950Ultras really easily with a few clicks.... plus you could make a 5950Ultra report itself as a 5900XT and own all the real 5900XTs on Futuremarks ORB....

The BIOS trick works with any two cards of the following: 7900GT, 7900GTO, 7900GTX, 7950GT. Not tested with a 7900GS, this would be the same situation as the OP is in.

The only reason I'm not 100% sure it will work for him is the fact that one card is only 20 pipes.

 

[Mousemonkey]

It doesnt really matter which card is in which slot while in SLi mode, the faster card always slows and masks RAM to be the same as the slower card.

Sorry mate, but I gotta pull you on this one, Ive been playing with 2 7900GT's all week, one is an Asus EN7900GT @ 450/650 the other is an XFX 7900GT oc @ 475/680 and there is a marked difference if the XFX is run in slot 1 or 2, 1 being the slot of better choice if for nothing else Coolbits seems to take it's reading from the card in slot 1.

 

[darkstar782]

It doesnt really matter which card is in which slot while in SLi mode, the faster card always slows and masks RAM to be the same as the slower card.

Sorry mate, but I gotta pull you on this one, Ive been playing with 2 7900GT's all week, one is an Asus EN7900GT @ 450/650 the other is an XFX 7900GT oc @ 475/680 and there is a marked difference if the XFX is run in slot 1 or 2, 1 being the slot of better choice if for nothing else Coolbits seems to take it's reading from the card in slot 1.

Hm, fair enough, but if thats the case its probably a bug, not as intended, and will likely change in a driver revision.

After all, there are 7900GTs out there clocked at 580/800, with more vGPU than is standard. Pair one of them with a stock (450/680 iirc) 7900GT and you stand a chance of damaging the 2nd card if that is the case.

You have tried it and I havent however, so I bow to your experience I'll mess about with my mates computer next time I'm round his (got his 7900GT and 7950GT working together, the 7900GT he has had for a while so is in the primary slot, and I didnt try moving it.)

If that is the case however, and the cards are stable at the faster speeds, then you should be able to set the faster speed stably with coolbits anyway, even if the cards are in the other order, no?

 

[prozac26]

I know they're both technically same, but SLI required same GPU version, like 7800GT with other 7800GT.

The difference in pipelines doesn't really make them "same". Whatever, I wouldn't the BIOS anyway.

 

[darkstar782]

I know they're both technically same, but SLI required same GPU version, like 7800GT with other 7800GT.

The difference in pipelines doesn't really make them "same". Whatever, I wouldn't the BIOS anyway.

Changing the Device ID cannot harm the card. I'd say its worth a try, seeing as he already has the cards there.

I agree that SLI with a 7800GT and a 7800GTX 512 is a complete waste of a 7800GTX 512, and the loss of 150MHz of core speed, half its RAM, and 4 pipelines on the 7800GTX probably means the speed gain from SLI will be negligible, its better than throwing the 7800GT away

 

[Mousemonkey]

I currently have the cards clocked @ 549/826 (1652 DDR) and the system is quite stable, but I was only able to get the clocks up to this by putting the XFX in the no.1 slot if it was in no.2 slot I could'nt get above 490/780, how much of that is down to mobo and other stuff I can't say.

looks like Hayden is Moto GP champion.

 

[prozac26]

Yea, it's probably going to end up crippling the card, so the effort might go to waste.

 

[darkstar782]

I currently have the cards clocked @ 549/826 (1652 DDR) and the system is quite stable, but I was only able to get the clocks up to this by putting the XFX in the no.1 slot if it was in no.2 slot I could'nt get above 490/780, how much of that is down to mobo and other stuff I can't say.

looks like Hayden is Moto GP champion.

Hm thats very strange, the only possible reason I can concieve of for that is that the bit on the other card that craps out above 490/780 is the compositing engine... but that wouldnt explain the difference in memory clocks.

Would be interesting to check the actual frequency of both cards with a meter, maybe they *aren't* running at identical clocks, I suppose with SFR the drivers could balance the workload taking clocks into account, although I wasnt aware of anything like this happening.

Wait... the 549/826 card could be running with looser memory timings, and the other card could be matching it in SLi, thereby enabling higher memory clocks.

Would be interesting to flash the slower card with the BIOS of the faster card, if you felt brave one day, and see if it has any effect

 

[Mousemonkey]

First off. congrats to :trophy: Nicky hayden, the new Moto GP World Champion :trophy: , as a die hard Valentino Rossi fan I'm choked, back on topic I don't know if I can find the brand of brave pill that I would need to start playing with the BIOS, the fact that I've got two slightly mis-matched cards playing so well together freaks me out so much (in a good way) that I really feel that pushing it may well tip things over the edge, although if you could have a play with your mate's 7950GT I would be interested in the results/benchies.

 

[Heyyou27]

Return the 7800GT; chances are you won't be able to get these cards to ever work in SLI, and if you do stability and performance may be an issue, let alone the time and effort you'll be putting in.