Thermal Performance

We've changed our thermal testing methods for this review, as we found that simply using high resolution gaming wasn't really cutting it any more. Even a game as demanding as Crysis will have peaks and troughs in terms of GPU load, whereas some GPU utilities, such as Nvidia's Badaboom media encoder or certain Folding@home work units will now place your graphics card under extreme load for extended periods of time.

With that in mind, we've selected FurMark 1.6.0 to stress graphics cards to their absolute thermal maximum. We've used the benchmark's Xtreme burning stability mode, running at 1,280 x 1,024 with 0xAA, 16xAF and waited for five minutes for the GPU to reach its absolute maximum temperature.

While this is an extreme GPU test, pushing cooling solutions to the limit, do remember our test rigs are all housed inside Antec 1200s, with all fans set to full speed to ensure our benchmarks run reliably. In less well ventilated cases, these cards will likely run a few degrees hotter, or will spin up their coolers to higher rpms to maintain GPU temperature.


While the Radeon HD 4890 runs hot when idle anyway, overclocking it so aggressively produces a further five degree increase, leaving the card idling at a toasty 56°C. Remember though that the Asus HD 4890 is, physically, a reference card, so such an increase isn't too surprising.


While at its stock speeds the Asus HD 4890 performs the same as any other reference HD 4890, hitting 82°C at load (a temperature set in the card's BIOS at which to spin up the card's cooling fan), when overclocked even an increased fan speed isn't enough to keep the card at 82°C, with our monster overclock resulting in both a noisier cooling fan and a GPU running 4°C cooler than it would at stock speeds.