It's a combination of overflowing vram and 8x PCIe. Now the vram is still overflowing, but it has twice as much PCIe of bandwidth to swap data to and fro when needed. Hence why it's smoother.
Which driver? Nvidia? Nah. Does anyone have any PCIe bandwidth data for x8 and how much BF3 would use in terms of bandwidth at x8? I always read that x8 would not impact performance, but then there was no BF3 ultra in those days. The SLI worked fine on all other games. Is it a BF3 bug? No. It is simply as others have stated, that ultra textures needs more than 1gb GDDR so the data is fetched from system and the data is not passed fast enough through x8 bottleneck. Now when u run BF3 on high, the data requirement drops as does mem usage, the data does not saturate the x8.
I have read some where (don't know where sorry) but that 8x slots just don't cut newer games like BF3 thats why I'm guessing that your cards didn't work together. But you have learnt a lesson and that's all that matters now
X8 x8 bandwidth is not harming my setup so I would say that is not the bottleneck. Yes it would perform slightly better on x16 x16. Were you trying to run ultra on 3d
Yeah the added vRAM on the 570s probably means that all the textures and whatnot fit in the vRAM without having to go to system RAM to swap things about. Hence none of the 8x bandwidth is being used for swapping.
I think the difference although only small between 1gb and the extra the 570 has could be enough. I must remind everyone that other than BF3 on ultra, all other games worked perfectly on SLI with none of the massive frame drops (perhaps Hard Reset also) so I don't think there was an issue with one 560 not keeping up with the other. I always checked the GPU usage for both 560ti and on games that had correct SLI scaling the usage on both GPU was 97 - 98% for DX11 games. There were a few games like Shift 2 and Crysis 2 that initially (until they released a patch) didnt scale properly but that would show up clearly on afterburner on screen display.
BF3 like having more than 1GB of vram thats why I got the 2GB vesion of my card to insure that I could play BF3 at the highest setting
I wish I had one too. Hasn't arrived yet. I have always preferred Nvidia because they always supported 3d glasses. I used to use Elsa Revelator shutter glasses with CRT monitor many years ago. I owned one ATI which I think was a 9800 or whatever it was. Bought it used with water and TEC fitted. It was a crap overclocker and the ATI control panel used to crash all the time. I know since then that ATI can be very good for overclocking but I still prefer Nvidia. A friend of mine running a business for printing complained his GPU kept crashing a few years ago. Turns out it was an ATI and I checked his then Vista OS and it showed the ATI control panel had crashed over 200 times! I advised him to get rid and buy an Nvidia 470. He never had issue since then. I have bought low end ATI and put in machines I built for people over the years and they ran fine though once the drivers were updated. I put a cheap ATI in my bro's PC 3 years ago and it overclocked well and gave quite an increase in FPS overclocked. I will stick with Nvidia though. ATI still arent sure if 3d vision will catch on. Meanwhile Nvidia have supported it long before their "3d vision" rebirth.
A GTX680 costs in the region of £400. Wouldn't personally spend that amount of money on a random purchase.
