Overclocking SLI Query (Nvidia)

[JQ-27]

Hi all,

 

Just got a quick query for anyone who's used to OCing SLI set ups, from what I've read up already I think that this is totally fine as I've noticed 0 performance decreases (as of yet) so let me get to the point.

 

My rig currently runs on x2 GTX 970s in SLI, during overclocking a week or so ago I noticed that both GPU's overclock rather nicely but during performance testing after overclocking I noticed that GPU1 wasn't boosting as high/under as much usage as GPU2. Although on Unigine everything looks fine stats wise, both boost up to the same but GPU1 still lags a little in usage.

 

I've tried swapping the GPU's around and it still gives the same results, so it can't be related to the GPU itself but I assume it's down to how SLI works/drivers/game usage on a case per case basis. Below I've got some screenshots which demonstrate it a little better.

 

GPU Usage/ClockSpeed for both GPU1 and GPU2 during a run on a game and two quick runs of Unigine (one with noticeable thermal throttle due to forgot to set it right)

http://prntscr.com/bhkgw0

http://prntscr.com/bhkhgw

 

[iBeast_M0de]

7 minutes ago, JQ-27 said:

Hi all,

 

Just got a quick query for anyone who's used to OCing SLI set ups, from what I've read up already I think that this is totally fine as I've noticed 0 performance decreases (as of yet) so let me get to the point.

 

My rig currently runs on x2 GTX 970s in SLI, during overclocking a week or so ago I noticed that both GPU's overclock rather nicely but during performance testing after overclocking I noticed that GPU1 wasn't boosting as high/under as much usage as GPU2. Although on Unigine everything looks fine stats wise, both boost up to the same but GPU1 still lags a little in usage.

 

I've tried swapping the GPU's around and it still gives the same results, so it can't be related to the GPU itself but I assume it's down to how SLI works/drivers/game usage on a case per case basis. Below I've got some screenshots which demonstrate it a little better.

 

GPU Usage/ClockSpeed for both GPU1 and GPU2 during a run on a game and two quick runs of Unigine (one with noticeable thermal throttle due to forgot to set it right)

http://prntscr.com/bhkgw0

http://prntscr.com/bhkhgw

 

This might be a CPU bottleneck, I don't like that word but I think that could be it. What CPU are you rocking?

[JQ-27]

8 minutes ago, iBeast_M0de said:

This might be a CPU bottleneck, I don't like that word but I think that could be it. What CPU are you rocking?

i7-4790k, so I doubt it's a CPU bottleneck. In hindsight I completely forgot to post the rest of my specs which would of helped,

 

i7-4790k - 4.6Ghz

MSI Sabertooth Mk1 Z97 MoBo

x2 GTX 970s

16Gb RAM

[iBeast_M0de]

1 minute ago, JQ-27 said:

i7-4790k, so I doubt it's a CPU bottleneck. In hindsight I completely forgot to post the rest of my specs which would of helped,

 

i7-4790k - 4.6Ghz

MSI Sabertooth Mk1 Z97 MoBo

x2 GTX 970s

16Gb RAM

Probably not no..

[iBeast_M0de]

What resolution are you running at?

[JQ-27]

7 minutes ago, iBeast_M0de said:

What resolution are you running at?

Only 1920x1080 60hz, just ran a little Witcher3 for another game comparison. GPU2 is basically locked at top Clockspeed, GPU1 does also get there but drops off now and then. But usage is more or less equal. Starting to think that it's just a querk of SLI. ¯\_(ツ)_/¯

http://prntscr.com/bhkxav

http://prntscr.com/bhkxp6

 

[iBeast_M0de]

1 minute ago, JQ-27 said:

Only 1920x1080 60hz, just ran a little Witcher3 for another game comparison. GPU2 is basically locked at top Clockspeed, GPU1 does also get there but drops off now and then. But usage is more or less equal. Starting to think that it's just a querk of SLI. ¯\_(ツ)_/¯

http://prntscr.com/bhkxav

http://prntscr.com/bhkxp6

 

It could be that you're just hitting a certain limit where the frames are depended on the CPU and not the GPU's there should be software that will show what frame times both components have

[JQ-27]

2 minutes ago, iBeast_M0de said:

It could be that you're just hitting a certain limit where the frames are depended on the CPU and not the GPU's there should be software that will show what frame times both components have

May look into that if it's actually hurting my performance, considering everything still runs perfectly fine I think I'll just shove it down as "SLI is a bitch" for now. Cheers anyway