Hello, I love this program. However I seem to have a problem with my frequency on my AMD R9 290X. As you can see in the attached screenshot, GPUTweak shows a constant 1255MHz, while HWiNFO fluctuates madly between 1116 and 1255. At first I thought this was a thermal throttling issue, but as you can also see my card never pushes 50C as it is water cooled, and these cards aren't supposed to throttle until 95C.
I'm not sure how GPUTweak determines the clock and what refresh period it uses.
But this might also be a power limit issue (not just temperature). Happens quite common to me when launching certain double-precision computing tasks. Have you tried to raise the power limit ?
Also, are you sure that the GPU was under a constant load during that period? What type of workload have you run?
If that won't help, please attach the HWiNFO Debug File capturing such situation for analysis.