Prevent "idle"/"low fps mode" on desktop

In windows 7, on a radeon card, sometimes the system will go into this weird low fps mode where firefox runs at 8 fps. I assume the OS is assuming you are idle by low usage even if you are running a browser. Could be a laptop feature (even though I am on desktop)?

You can temporarily fix this by dragging the firefox window around, this is apparently gpu intensive enough to get the system to go back to 144fps mode or whatever for a few minutes.

Any way to get it to run at full power forever?

Does this happens with Firefox only, or any other program suffers the same?

All programs suffer it.

I think disabling AMD's ULPS setting fixed it? not sure, fps still stutters sometimes but it's much less.
Apparently doing weak things in browsers can trigger ULPS.

Never mind, disabling ULPS does nothing.