Overclocking In SLI
Overclocking in SLI may yield a 15-20% performance boost, or more. For reference, my own personal results in 3DMark Fire Strike are available here. I'm working with an EVGA Superclocked version of the 980s, so I'm starting from an already-high 1266MHz base clock rate and 1367MHz GPU Boost rating.
Overclocking cards in SLI is not always straightforward, however. In particular, we've noticed that the bottom card (that is, the one in the lower PCIe slot), regardless of voltage input settings, ends up operating at a lower voltage than the top one. That is undesirable, as it appears to limit the overclocking potential of both cards, since they can only go as fast as the lower card, with its limited voltage increase, will allow.
When asked about the voltage inconsistency, Nvidia answered, "We don’t run each chip at the exact same voltage. There’s variation from chip to chip." For 99% of users, this shouldn't be an issue they need to worry about. If the voltage inconsistency really bothers you though, there is a workaround: unlink the card settings in a tool like PrecisionX and set the card with the lower voltage at a higher core clock offset than the other. This won't lead to core clock rate differences; the frequencies will still be locked at the same number. But it will raise the voltage of the card to match. Not elegant, but it works!
Do you think we'd see 1080p monitors with 200hz+ in the future? Would it even make a difference to the human eye?
I also believe that alternating frames is utter crap. The fact that this has become the go to standard is a travesty. I dont care for fake fps, at the expense of consistent frames, or increased latency. If one card produces 60fps in a game. I would much rather have 2 cards produce 90fps and both of them work on the same frame at the same time, then for 2 cards to produce 120 fps alternating frames.
The only time 2 gpus should not be working on the same frame, is 3d or vr, where you need 2 angles of the same scene generated each frame. Then ya, have the cards work seperatly on their own perspective of the scene.
However, If i need to buy 2 980s to run a VR set or a 4K display Ill just wait till the prices are more mainstream.
I mean, in order to have a good SLI 980 rig you need a lot of spare cash, not to mention buying a 4K display (those that are actually any good cost a fortune), a CPU that wont bottleneck the GPUs, etc...
Too rich for my blood, Id rather stay on 1080p, untill those technologies are not only proven to be the next standard, but content is widely available.
For me, the right moment to upgrade my Q6600 will be after DX12 comes out, so I can see real performance tests on new platforms.
I had my eye on the two Acer monitors, the curved 34" 21:9 75Hz IPS, and the 27" 144HZ IPS, either one really for a future build but this piece of info tells me my i5 will be a problem.
Could it be that Intel CPUs are stagnated in performance compared to GPUs, due to lack of competition?
Is there a way around this bottleneck at 1440P? Overclocking or upgrading to Haswell-E or waiting for Sky-lake?
While true from a certain perspective, it should be clarified that you need 2 of the same number designation. As in two 980's or two 970's. I fear that new system builders will hold off from going SLI because they can't find the same *brand* of card or think they can't mix an OC 970 with a stock 970 (you can, but they will perform at the lower card's level).
PS. I run two 670's just fine (one stock EVGA and one OC Zotac)
What you say -was- true with 6xx class cards. With 9xx class cards, requirements for the cards to be identical have become much more stringent!