Verdict: A factory-overclocked HD 4870 but little additional speed.
We currently live in a rare golden age of super-close competition in the graphics card world. The major news is that ATI is back, with its Radeon HD 4870 bashing the more expensive Nvidia GeForce GTX 260 in many tests. The Asus EAH4870 TOP uses a pre-overclocked Radeon HD 4870 GPU, hoping to give Nvidia even more of a headache. However, with a higher price as well as increased clock speed, the Asus TOP will have to beat the GeForce GTX 260 soundly to be worth buying.
The Asus TOP's GPU frequency has been raised from 750MHz to 815MHz, and the GDDR5 memory speed increased from 1.8GHz (3.6GHz effective) to 1.85GHz (3.7GHz effective). The overclocked memory leads to increased memory bandwidth, boosting it from 115GB/sec to 118.4GB/sec, fractionally more than the 112GB/sec from a stock-speed GeForce GTX 260.
Comparing the performance of the Asus TOP with that of a stock-speed HD 4870, we can see some definite improvements. The biggest increase was in Race Driver: GRID at 1,920 x 1,200 with 4x MSAA, in which the Asus TOP ran at 70fps minimum as opposed to the 66fps of the stock-speed card.
However, while playing our other test games, we witnessed increases of just 1-2fps over a stock-speed HD 4870. Crysis is a good example; at 1,680 x 1,050 with 2x AA, the Asus TOP only managed the same disappointing 24fps minimum frame rate as a reference HD 4870.
We found an XpertVision stock-speed GeForce GTX 260 on www.ginger6.com for £189. This card provides an interesting comparison with the Asus TOP. In both Call of Duty 4 and Race Driver: GRID, a GTX 260 is bested at all resolutions by a stock-speed Radeon 4870, so it's no surprise that the Asus TOP is even faster. However, Crysis remains a different story, as a GTX 260 runs the game a bit faster than the Asus TOP, achieving a 26fps minimum at 1,680 x 1,050 compared to the 24fps minimum of the latter. The Zotac GeForce GTX 260 AMP! makes the comparison even more interesting, as the overclock applied to this card by Zotac yields a minimum of 31fps in Crysis at 1,680 x 1,050 with the reference cooler. If the ability to play Crysis weighs heavily in your criteria of what you expect from your next graphics card, this could sway you toward the GTX 260.
The Asus TOP produced a total of 1,907ppd in our Folding@home test, compared to 1,812ppd from a stock-speed card. With the Asus TOP installed, our test system drew up to 356W from the wall while folding, and up to 376W during game testing. Note that the overclock on the Asus TOP also makes it noticeably noisier than a quiet stock-speed HD 4870, as the folding test revealed all too well.
A little more juice can often be squeezed out of a pre-overclocked graphics card, and by using AMD's GPU Clock Tool v0.9.8, we raised the GPU frequency from 815MHz to 860MHz. This increased the minimum frame rate of CoD4 at 1,920 x 1,200 by 2fps to 42fps.
We managed to overclock the GPU of the Asus TOP to 880MHz but, while CoD4 ran without any graphical corruption, we saw no further increase in the frame rate. Settling on a GPU speed of 860MHz, we increased the memory from 1.85GHz to 1.98GHz (3.96GHz effective), and managed to squeeze a further 1fps out of CoD4 at 1,920 x 1,200. Our overclocking increased the minimum frame rate by 3fps at 1,920 x 1,200, so we considered our efforts to be a well-spent 20 minutes.
Conclusion
Looking at the numbers, the Asus EAH4870 TOP is faster than a stock-speed GeForce GTX 260 (and even the pre-overclocked Zotac GeForce GTX 260 AMP!) in CoD4 and GRID. However, a GTX 260 is slightly faster in Crysis, and the Zotac review suggests that overclocking a GTX 260 will also give you a great card for Crysis. This is significant if Crysis is a good indication of how a card will run future games, but note the hypothetical 'if' in that statement.
The overclock from this TOP card doesn't give enough extra speed to justify the £24 it costs over a stock-speed card, but further overclocking yields a good speed boost. As this card and the GTX 260 are so similar, we would either buy an HD 4870 for £170 or get the Zotac for guaranteed great Crysis performance.
