Need help with SLI.

[Tim]

Good morning everyone.

I purchased a second Evga GTX 980 ACX 2.0 superclocked card to match with the one I already own. I plugged the new card into the lower slot, and everything seems to be running fine after enabling SLI in the nvidia control panel, but I've noticed one thing that I'm not sure about.

The second card (the newer one), although being the exact same EVGA part #, seems to be running at about a 40mhz higher clock speed than the other card. Is this normal?

 

[n0x1ous]

yes - the cards will boost to different clocks depending on temp, power limit etc. Perfectly normal

 

[Tim]

yes - the cards will boost to different clocks depending on temp, power limit etc. Perfectly normal

If that's the case, should I put the card that tend to boost to a higher clock in the first slot, or will that not even matter?

 

[n0x1ous]

What typically happens is the top card runs hotter than the bottom card so its possible if you swap them your new top card will not boost to the same level as when you had it on the bottom - all depending on your temp and power targets.......

TLDR: I would just leave it as is and let the Nvidia driver do its job of load balancing.

 

[Tim]

Sounds good. I've got backplates coming in today, so I might experiment anyway seeing as I'll have to take the cards out for installation. I did notice the top card runs a little hotter

Appreciate your quick responses.

 

[aigomorla]

are u running multi monitors?

if you are, the top card will also not downclock to lowest values.

 

[Hinda65]

don't be surprised if the top card runs 10F hotter than the bottom...that's what I tend to see with 780's and the ACX cooler

 

[bowler484]

How are you monitoring the cards to check clocks? Do you have something realtime like Precision-X running in game? Or are you relying on GPU-Z?

I have 980 SLI. One card runs 1380 Mhz and one runs 1420 Mhz out of the box.

When put together, they run at the 1380 Mhz of the lower card.

SLI Mhz should be locked together. It keeps the cards in sync.

 

[Hinda65]

I measure mine with precision...the clocks are rarely (if ever) in sync.....I have slightly different versions....ones the standard superclocked ACX the other is the FTW ACX

 

[Termie]

If you use MSI Afterburner, it allows you to sync the clockrates. EVGA Precision may do it too.

It's not optimal to have them running out of sync - just one more variable to throw off the frame pacing.