Coverflow performance and SLI

[nosh]

Just wanted to share something that may help some people. I have been having considerable performance issues with Coverflow on the PC I use for development which is running 2 980's in SLI, custom watercooled, needless to say the performance issues are not spec related. Today I was determined to figure it out, I tweaked advanced video settings, turned off gsync, changed my refresh rate, removed my video drivers and did a clean install, tried a bunch of things. Last thing I tried was turning off SLI and sure enough that was it. I have no idea why SLI would cause that, maybe my other card is defective, maybe its because im running an i7-5820K so the second card is only getting 8 pcie lanes in SLI, no idea. Curious if this resolves issues for anyone else.

[SentaiBrad]

SLI is actually very poorly supported. A shockingly small percentage of games even utilize the extra GPU, let alone your OS or regular applications. Emulators certainly don't use SLI setups. It's been a very common point of conversation about SLI setups, that they do cause performance degradation more than they increase performance. If you're playing the games that support it fully, then that's awesome, but the more cards you add to your PCI slots, the slower each subsequent device gets, and on some motherboards even the earlier devices will get slower. So you're adding in double the power, but then it's being cut off to only a portion of it's power due to PCI Lanes, on top of only some software utilizing it. On some motherboards, I saw scenarios where the single GPU was at 16x, but putting in a second GPU for SLI dropped each down to 8x, effectively nulling the effect of ever adding in a second GPU, and now causing issues because it's present. It's not exactly that cut and dry, especially because some of the ogod motherboards now will not drop as many lanes as fast anymore, but still. The issue is still there.