SLI Not performing as expected.

[garsands]

If this is your card that you linked to in your opening post then no
Gainward GeForce GTX 570 1280MB GDDR5 PCI-Express Graphics Card

 

[Cleeecooo]

But isn't my VRAM close to 4GB according to my control panel and 3DMark results?

No, you have 1.3GB

 

[Mackey18]

But if I have 2 cards I have 2*1280MB don't I? Isn't that the whole point of getting 2 cards?

 

[garsands]

Have you run msi afterburner while playing you can then view a read out like this?
This will show you what your card are doing.

[/IMG]

 

[garsands]

And no RAM does not double up both cards only use one single VRAM

 

[Mackey18]

So the VRAM on the 2nd GPU does nothing? That's a shame.

Anyway, I removed the OC on my CPU as it had no performance increase and nearly blew up my CPU (100dC)

Mike

 

[Mackey18]

Garsands I ran it while I was doing a 3DMark test and it showed both cards working together.

Mike

 

[Mackey18]

With MSAA off BF3 runs at 63fps. With it on it's exactly the same FPS as it would be with one card, 20.

 

[ALXAndy]

With MSAA off BF3 runs at 63fps. With it on it's exactly the same FPS as it would be with one card, 20.

Right so did you try the adaptive performance to prefer max performance thing I posted?

If not? then SLI isn't working. Check your bridge, or, resort back to single card gaming because it's much less aggro.

 

[Braka]

buy a good 1080/1200 res monitor ;p and get rid of that high res ur using ^^

 

[garsands]

If it showed both cards working at the same usage & same MHz ect then both cards are working fine in SLI.

I had GTX470 1280Mb running at that res for over a year & it was bad times the card just could not run at the res with max settings.

It's a expense res to game at if you want max eye candy & at that res you do why else play that high.

I have just spent £1,100 on two cards it's crazy money, but that's the price you pay if you want max settings.

 

[Mackey18]

I haven't tried that yet, thanks for reminding me. Just disabled SLI to double check the FPS of BF3 with MSAA on. Will have to devise some sort of test to see if the second card is working.

The setting you want me to change is currently set to nVidia recommended or something, shall I still change it?

 

[garsands]

buy a good 1080/1200 res monitor ;p and get rid of that high res ur using ^^

+1

It's a lot cheaper.

 

[Mackey18]

Ok, beginning to think this is a PSU issue. I distinctly remember testing my 1st card on MSAA and I used to get around 20FPS. Now it's down to 8FPS without SLI (but with 2nd card still plugged in).... Correct me if I'm wrong, but that's not right. Perhaps the PSU isn't supplying enough power to the cards.

Cheers,
Mike

 

[ALXAndy]

Ok, beginning to think this is a PSU issue. I distinctly remember testing my 1st card on MSAA and I used to get around 20FPS. Now it's down to 8FPS without SLI (but with 2nd card still plugged in).... Correct me if I'm wrong, but that's not right. Perhaps the PSU isn't supplying enough power to the cards.

Cheers,
Mike

If your PSU was running out of juice you would hear a bang, smell that familiar electrical burning smell and your PC would be dead.

Cards do not throttle when not given enough power, they simply switch off and cut out the PC.

Most power supplies (good ones) have circuitry to switch off if current gets too high. So you wouldn't have performance issues, you would have a PC that turns itself off when it gets too much.

Try what I explained to you first. Remember - 99% of computer problems are software based, the other 1% are user error

 

[jonnylaris]

Ok, beginning to think this is a PSU issue. I distinctly remember testing my 1st card on MSAA and I used to get around 20FPS. Now it's down to 8FPS without SLI (but with 2nd card still plugged in).... Correct me if I'm wrong, but that's not right. Perhaps the PSU isn't supplying enough power to the cards.

Cheers,
Mike

Lol man I told u this like twice already.

It's definatley a PSU issue imo.

 

[Mackey18]

Ok fair enough. I'll redownload/reinstall the drivers now. Let's see what that does.

Ok tried Skyrim with and without SLI both at ~47FPS with no V-sync.

Mike

 

[ALXAndy]

Lol man I told u this like twice already.

It's definatley a PSU issue imo.

According to his sig he has a 650w Antec Tru power.

According to Antec's site that means.. 2 22a rails and a third 25a rail.

OK, now we can agree that a GTX 295 single PCB eats more power than a 570 yes? considering its a hybrid 275 sort of thing x2 at 260 clocks?

Well I run mine on a 625w Modu II. A PSU that has three 22a rails. And I have never, ever had any problems.

To support this (the only reason I did it at all) is this.

http://guru3d.com/article/enermax-modu82-ii-625w-psu-review/6

Please pay close attention to -

These are the components used:

nForce 790i motherboard (has high power consumption)
Core 2 Quad QX 9770 Processor (overclocked to 3.6 GHz)
2x GeForce GTX 295 primary (4 GPUs)
1x GeForce GTX 280 (PhysX)
3 GB Memory DDR3 @ 1600 MHz
Optical Drive x1
HDD x1

And it worked perfectly fine.

All I would be concerned about is the rail loading. Make sure both cards are not on the same rail (it should lay them out in the manual).

But there is no way on earth that two 570s (throttles and all) will use more power than two GTX 295 co ops.

 

[garsands]

If it was PSU issue you would see this....

Maybe your 650w PSU doesn't provide enough wattage causing the cards to lose power?

Do you see this on your system ?
You have all the tools there to find out.

 

[setter]

Psu could be the culprit, with an oc'd i7 920 and a pair of gtx 470's, im seeing a draw at the wall of 630w when gaming, (corsair hx 850w). Seen sb users with dual 470's reporting a slightly lower power draw, (20-30w ono) but enough to seriously work a 650w psu.