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.


The low noise custom cooler performs well when the card is idle, remaining as whisper quiet as we've come to expect Sapphire's Vapor-X coolers to be while cooling the GPU 7°C lower than the stock card, a fine result. What's also pleasing is that the card is able to do this without spinning the cooling fan up to excessive noise levels, with the maximum speed we saw at idle of 1,500rpm perfectly acceptable to our ears, although not silent, as we found with the Sapphire HD 4870 1GB Toxic.


At load things don't look as good though, with the Sapphire Radeon HD 4890 Atomic running at the 82°C as the stock clocked Radeon HD 4890 under identical circumstances. However, this is still well within the safe running temperatures for the GPU, and comes without the irritatingly intrusive fan noise of the 4890's stock cooler, which spins up to intrusively noisy levels under such ultra-heavy loads. Even at full load the Sapphire HD 4890 Atomic's fan never sped up above 1,740rpm, and remained pleasingly quiet throughout. Given that the card's under no threat of overheating and was perfectly stable at these higher temperatures even at full load for extended periods, we'd call this a win for the Sapphire Vapor-X.