Noob question about GPU overclocking (SLI/Crossfire)

[STRMfrmXMN]

So say you have two GTX 970s. If you want to overclock them when in SLI, do both run at the same clock speed when you overclock them? Are they both guaranteed to be able to reach the same speed (silicon lottery)? Same goes for if you have 3/4 card in SLI. If you overclock them, do they all run at the same memory clock and core clock or do you do it one-by-one? I only have one GPU so there's no testing this for me.

[Godlygamer23]

Programs like Afterburner have an option(which is enabled by default) to apply the same settings to the cards. No, they are not guaranteed to hit the same clocks. 

[STRMfrmXMN]

Programs like Afterburner have an option(which is enabled by default) to apply the same settings to the cards. No, they are not guaranteed to hit the same clocks. 

If you disable that option can you set each card to it's own clocks?

[Godlygamer23]

If you disable that option can you set each card to it's own clocks?

Yes, but you're not gaining any benefit to doing that. The slowest card will bottleneck the fastest one.

[STRMfrmXMN]

Yes, but you're not gaining any benefit to doing that. The slowest card will bottleneck the fastest one.

OK, all makes sense now. Thanks!

[XiaoPineApple]

in sli/cf it use the lowest setting

ex. 4gb vram + 2gb vram.

u will only use 2gb vram for both cards

same for clockspeed and memory