SLI adding 16ms latency?

[terablaze]

I'm looking to play multiplayer games with the least amount of input lag possible. I even made sure the TV I recently purchased had an input lag under 20ms. I understand that two video cards in SLI, will take an additional frame to render. Am I to understand that this will add 16ms of lag to my games, nearly doubling my overall input lag?

 

[MichaelK_]

Yes, SLI will always increase latency, although you don't need to enable it on multiplayer games since they're usually light on graphics. If you really care about input lag, get a dedicated gaming monitor; they can go down to 1m on a TN panel, or 4 on IPS.

 

[Mr Kagouris]

No, that's not how AFR (alternate frame rendering) works. AFR works by getting one GPU to render one frame and at the same time getting the second one to render the next. This adds a tiny bit of latency, but nothing even remotely significant. The tons of extra frames will actually offset this because higher framerate results in lower frame latency.

Also the response time touted by monitors is NOT input lag, it's how fast they can change colors on individual pixels.

 

[MichaelK_]

No, that's not how AFR (alternate frame rendering) works. AFR works by getting one GPU to render one frame and at the same time getting the second one to render the next. This adds a tiny bit of latency, but nothing even remotely significant. The tons of extra frames will actually offset this because higher framerate results in lower frame latency.

Also the response time touted by monitors is NOT input lag, it's how fast they can change colors on individual pixels.

It adds a frame worth of latency, which is arguably significant. Compared to a single card that can't reach the framerate limit, the latency CAN be lower, but compared to a single more powerful card, SLI will always have more latency. If you're looking for "the least amount of input lag possible", SLI is not the way to go.

 

[Mr Kagouris]

Yes it is true that a single more powerful card is preferable in such situations.