MoBo for SLI

when looking at a motherboard to SLI with, does x16/x16 dominate any other configuration, i.e. x16/x8; x8/x8; x16/x4. Is there a differece in performance or does the SLI bridge connector solve any bandwidth problems?
Dominate? No.

It's difficult to calculate the differences in performance for *any* two gpus running *any* game at x16-x16 vs x16-x8 vs x8-x8. The question is whether *this* game would gain (noticable) fps from *this* pair of gpus if I went from, say x8-x8 to x16-x16.

The best analysis I've seen to date is this one (I've linked you to the SLI-summary page, but you may want to read other sections and the conclusion):,2696-16.html

If you are considering SLI, I think its fair to say the following:

1) Avoid using an X4 slot. You *will* most likely see a performance hit.
2) x16-x16 is theoretically the best (duh).
3) x16-x8 *may* show a few percent performance loss while gaiming vs x16-x16, but most likely not.
4) x8-x8 will lose you a few more percent of SLI scaling in general, and I'd personally avoid it if contemplating two very high end cards (eg 2x580).

An x16-x8 mobo - in my opinion - is a very reasonable choice for a rig gaming at 1920 and wanting to preserve the option of SLI, or when SLIing mid-range cards.

At 2560 or higher resolution, I'd probably want x16-x16 because today's games begin to challenge today's best gpus at those resolutions. And I wouldn't want to give up even a few percent of performance.


Aug 27, 2011
agree with @twoboxer using of x8-x8 slots will lose peformance only 5% but do not worry about it you doesn't feel it your games will run on maxed with a pair of 2x gtx580 but make sure your psu can handle these both and a powerful cpu like 2500k,2600k.

i'd be doing SLI 460's at 1920x1080 so it'd be mid range cards