Radeon 280 Clock Speed Increases and Decreases Rapidly

[Kalius]

I am trying to get a stable overclock for my r9 280 Windforce 3x, which comes with a boost clock of 1072 MHz and a core clock of 950 MHz. I noticed that the card would never reach the boost clock, unless I increased the power limit. However, once I increase the power limit, the clock speed jumps up and down from 950 MHz to 1072 MHz sporadically. Though the clock speed increasing does increase FPS, I can't understand why this is a feature of this graphics card. I can use my other 280, which does not have a boost clock, to run games at a constant clock speed.

Here are some images of my chart when running a FurMark stress test.

with power limit +20% (causes boost to engage), I received 95 avg fps in 800x600 gpu stress test.

with power limit +0% (causes no boost), I received 68 avg fps in 800x600 test.

Is the boost clock working as intended here? Would it be wise to disable it?

 

[Kalius]

In a video I found online, the clock speed continuously changes from 950 to 1072 while running stock voltage. https://youtu.be/bf-HWMfw7Uk?t=249 I must increase the voltage to +20% to have the same effect as him on +0%. When he increases the voltage to +20%, his clock speed stays on 1072. Something is wrong/different with my card.

 

[TJ Hooker]

Don't use furmark, it's a very unrealistic stress test. Try running a different benchmark like Unigine valley/heaven, and see what the clock does. It's entirely possibly you're still hitting your power limit in Furmark even with +20% due to how demanding it is.

In general, if you're running a constant heavy load your clock speed should stay at max unless you're hitting thermal or power limits. At least in my experience.

 

[Kalius]

Don't use furmark, it's a very unrealistic stress test. Try running a different benchmark like Unigine valley/heaven, and see what the clock does. It's entirely possibly you're still hitting your power limit in Furmark even with +20% due to how demanding it is.

In general, if you're running a constant heavy load your clock speed should stay at max unless you're hitting thermal or power limits. At least in my experience.

Thanks, I'll try heaven benchmark. Anyways, the clock speed jumping around is seen in heaven on the video I linked one post above. I cannot figure out how to disable the boost clock, except a profile on app by app basis in radeon-pro which emoves power saving features and it slightly tedious. I believe without the boost clock feature on this card, I would be able to find a stable core clock speed better. This is because whenever I increase the core clock speed, it fluctuates between the speed I set and another, 10% slower speed (the speed I set is regarded by the card as the "boost" speed, and it downclocks to the "core" speed automatically).

EDIT: I am reaching the boost speed (1072 MHz) consistently in heaven at +10% power, so I guess FurMark was really just using a lot of power. Thank you Though, I still do not understand the boost vs core clock speed, it seems like it makes it hard to determine the proper voltage, since it keeps downclocking. I'll run Heaven at max settings, then keep increasing the core clock until some instability happens.