2-way SLI on Maximus V Extreme - best slots 8x/8x or 8x/16x?

[feniks]

I am looking at ASUS MVE manual and it seems that for 2-way SLI ASUS proposes using Intel CPU native bandwidth for both cards (8x/8x natively) using slots PCIe3.0_1 (top first) and PCIe3.0_2B (third from top). I know that switches/bridges may cause some lag, so it makes sense *IF* each of cards doesn't exceed the PCIe3.0 8x bandwidth (I think 670 2GB cards don't but I am unsure of it).
Also this configuration allows for better air flow between cards which probably matters if one relies on air cooling ... I don't, both cards are water cooled.

however I see there is also another config possible which is based on 3-SLI configuration and for 2-SLI it would suggest using both top first and second slots, PCIe3.0_1 & PCIe3.0_2A respectively for x8/16x.

tomorrow I will be installing my second 670 2GB for 8x/8x config for now and I hope it works fine (no lag related to PLX chip switching).

does anybody have some benchmarks comparing same cards and CPU clock (and memory) running 2 cards in each of mentioned configurations?

Thanks!

[stackoverflow13]

If you notice all that evga have done is double the clock value figure of asus because the 690 is 2 cards ie 2x 3004mhz. This is band marketing & wrong. all gtx 690's are the same. all have a memory clock of 3004MHz.

[rog-classified]

stackoverflow13 wrote:
If you notice all that evga have done is double the clock value figure of asus because the 690 is 2 cards ie 2x 3004mhz. This is band marketing & wrong. all gtx 690's are the same. all have a memory clock of 3004MHz.

you mean there are no different between asus and evga card? if its so ill go with asus. thankx mate.

[feniks]

actually the effective memory clock on 600 series is like that, around 6GHz while most software apps reports it halved (3GHz), it's normal. both specs (EVGA & ASUS) are correct though, just using different methodology 😉

for instance my 670 memory runs at 3506MHz as reported in GPU-Z or Precision X, but in fact that is effective 7012MHz. GDDR memory... effective double data rates, just like with DDR3 RAM, CPU-Z will report 1200MHz while one is running 2400Mhz.