Even in a cold room, we can plainly see the impact of thermal throttling in 3DMark's Fire Strike test using an air-cooled Radeon R9 290. Overclocking helps fix that board's performance, since I'm increasing the fan speed and power limit. But the liquid-cooled card's higher frequencies assure its victory.
Though it’s possible to force power throttling on the CryoVenom at stock settings, this only happens under unusually heavy loads like FurMark. This phenomenon would have been easier to trigger with the clock rates turned up, except that I also increased the power limit by 50%, creating headroom.
The CryoVenom R9 290 retains its lead through 3DMark’s Fire Strike “Extreme” settings.