ASUS adds Voltage Tweak to Radeon HD 5800 series
 

We've yet to test it for ourselves on AMD's latest cards, but the figures we're being quoted are impressive. According to ASUS, its Radeon HD 5870 can have its voltage raised from 1,15V to 1,35V, resulting in a GPU clock speed bump from 850MHz to 1,035MHz and a rise in memory speed from 4,800MHz to 5,200MHz. That's essentially the fastest single-GPU graphics card made faster, and we reckon those figures may give an indication of Radeon HD 5890 performance.

For those wanting to save a few pennies, ASUS' Voltage Tweak-packing Radeon HD 5850 can raise voltage from 1.088V to 1.4V. That'll increase GPU clock speed from 725MHz to 1,050MHz and memory clock speed from 4,000MHz to 5,200MHz.

http://www.hexus.net/content/item.php?item=20377

A Radeon HD 5870 with 1Ghz core will beat the GTX 295; and the HD 5850 at 1050Mhz might well close the gab with the HD 5870, or even best it!:)

I want one, massman two :p