Asus is the first AIB partner that will alter the reference frequencies on the HD 5800 series cards. Asus has decided to use its Voltage Tweak feature on these cards, which allow them to achieve higher clocks by raising the GPU voltage. It is a nice add-on and it looks like Asus found out that these cards overclock nicely with a bit of additional voltage to the GPU.

Asus will launch a total of four cards, two HD 5870 and two HD 5850, where the only difference between the models is the bundle. One will come with the Dirt 2 game voucher while other one will be shipped without it, and will thus end up cheaper.

With no voltage changes applied, Asus' graphics cards are running at reference 850/725MHz for the core and 4800/4000MHz for the 1GB of GDDR5 memory. When Voltage Tweak comes into play, the HD 5870 can be overclocked to 1035MHz for the GPU and 5200MHz for memory by just raising the voltage from 1.15V to 1.35V. With the HD 5850 it gets even better as it can be overclocked via Voltage Tweak to 1050MHz for the GPU and 5200MHz for the memory by raising the voltage from 1.088V to 1.4V.

By the looks of things and the figures, the HD 5850 is quite a jewel, and this might be a great card if you are into overclocking. According to Asus, this overclock raised the 3DMark Vantage Extreme Preset score from 8,087 to 9,252 for the HD 5870 and from 6501 to 8987 for the HD 5850. This also means that an overclocked HD 5850, which has less stream processors, might be capable of beating the higher priced HD 5870 at reference clocks, at least when talking about 3Dmark Vantage. Of course, we need not remind you about the price difference between these two cards.

AMD might not be happy that Asus offers a voltage change option to its customers, but Asus will of course do anything to get an edge against the ever-tough competition on the market.