Although all five custom Radeon R9 280X cards are much the same in gaming and cooling performance, they still have subtle variations that make some better than others -- and one better than the rest in our opinion.
Considering it's a mid-range to high-end graphics card, the R9 280X will likely find its way into mid-towers. The majority of these cases require you to sacrifice storage space to fit graphics cards longer than 300mm. The NZXT H440, for example, will only accept the HIS R9 280X iPower IceQ X² Turbo or Sapphire Vapor-X Tri-X OC R9 280X if a hard drive cage is removed.
The Gigabyte, Asus and MSI cards are all 280 to 290mm long whereas HIS and Sapphire's measure about 310mm. While the Sapphire card does employ a triple-fan configuration, Gigabyte achieved the same feat in less than 300mm. Moreover, when it came to cooling performance the Gigabyte card only ran a degree warmer than Sapphire's.
If you want the card with the best cooling, the HIS R9 280X iPower IceQ X² Turbo ran at 65 degrees or less, but this was still only four degrees lower than the hottest R9 280X (Asus').
Speaking of which, the Asus R9 280X DirectCU II TOP was a little underwhelming in other areas too. It's been a while since we tested an Asus graphics card but from memory they were great. Unfortunately, our sample didn't overclock particularly well and was overall quite average.
That said, we know Asus heavily recycles review samples. Chances are, this is an early production or possibly even pre-production card that has seen more than its fair share of torture. That might explain why it fell 40MHz short of the target set by Gigabyte's R9 280X WindForce 3X OC. Of course overclocking will vary from card to card anyway, so our results are only a rough guide.
When it comes to pricing, the Asus R9 280X DirectCU II TOP, Gigabyte R9 280X WindForce 3X OC and MSI R9 280X Gaming 3GB (forget the 6GB model) cost $300, the HIS R9 280X iPower IceQ X² Turbo 3GB is a little less competitive at $330 and the Sapphire Vapor-X Tri-X OC R9 280X 3GB is at $340.
Overall, we feel Gigabyte's card is the best R9 280X available right now, offering the most out of box performance, best overclocking results, solid cooling and a competitive price. The R9 280X WindForce 3X OC's only weakness was in power consumption, drawing around 10% more total system power. However, that's due to Gigabyte's auto voltage feature, which we think is worthwhile for the added ease of overclocking and extra stability.
If the HIS R9 280X iPower IceQ X² Turbo were a little cheaper and shorter it would have been a real threat to Gigabyte's card and we might have picked it instead. The MSI R9 280X Gaming 6GB is also a close second, though I wish we had gotten to test the 3GB model.