GPU overclocking instability?

[Krister Arvesen]

Hi! I sat down to do some overclocking on my Sapphire Tri-X R9 280X... and I saw some unexpected and weird results... I started out at 1100MHz as I know my card is capable of that (it's not factory OC and comes stock at 1000MHz)... I decided that I would just use the Tomb Raider benchmark as a quick indicator to whether the OC was stable or not and to see any performance differences...
@1100MHz I got a minimum of 84 a max of 124 and averaged 104.5 fps... then I started increasing the clock bit by bit and saw improvements all the way until 1150MHz where I got min: 86, Max: 128 and Averaged about 107.5 fps... then I tried bumping it up to 1160MHz (remember I did not overvolt) and fps went down drastically! (averaged about 72fps) I did not see any stutters or weird things it ran all the way through the benchmark so I thought that I had reached the limit for what my card could do without overvolting it... so then I wen't back and figured that I would try it once more at 1145MHz and see what number I got there before going to a more stressing benchmark like valley in order to really see if it was stable... but when I ran it at 1145 it was still only averaging about 70 or so fps? even though it ran with 30fps more at 1100MHz and even better with 1150MHz...
I checked with GPU-Z and I didn't experience any thermal throttling or anything... the card ran at the set speed through the whole benchmark and it barely touched 60C with fans only going up to about 40% at most...
so is there something wrong with my card or is it Tomb Raider acting up weirdly?

 

[AMDFaith]

Your card looks like it's throttling clock speeds to match the stock voltage settings.

Did you touch the memory freq. numbers?
Are you using Trixxx?

 

[Krister Arvesen]

Your card looks like it's throttling clock speeds to match the stock voltage settings.

Did you touch the memory freq. numbers?
Are you using Trixxx?

I did not touch the memory freq. at all... and it was not throttling... that's why I find it so weird... when looking at GPU-Z I saw that the card was running at the set boost freq. through the whole benchmark... In GPU-Z everything looked normal... temps weren't high, and bothe memory and core ran at their max through the whole thing... voltage was stable and the fans had plenty more power to give...

 

[Krister Arvesen]

Your card looks like it's throttling clock speeds to match the stock voltage settings.

Did you touch the memory freq. numbers?
Are you using Trixxx?

Think I found something... I ran the Valley benchmark and it said the GPU was only running at 850MHz even though GPU-Z says 1000MHz and it's set to 1000MHz in AMD Overdrive atm... should I download MSI afterburner and try to use that?

 

[Krister Arvesen]

Ok so now I'm sure Tomb Raiser is acting weird on me... I suspected that AMD Overdrive was the problem so I installed MSI Afterburner, rebooted the system and started overclocking again, this time with Afterburner and using Valley instead of Tomb Raider, got a stable OC at 1140MHz (+140MHz) Core and 1650MHz (+150MHz) on the memory (could probably have pushed the memory a bit more) and I almost reached my goal of getting past a 2000 score in Valley (with these settings I got 1992) on the Extreme HD preset ;D Can probably get past 2000 if I OC my CPU as well... but anyway, after this I went back to tomb raider and tried the benchmark, and what do I see... all the sudden my GPU is back at 850MHz and I had to reboot again to get my OC back...