Overclocking

To find the maximum overclock of our card we used a combination of ATITool's successor and our benchmarking suite.
The overclocks listed here were achieved with the default fan and voltage settings as defined in the VGA BIOS. Please note that every single sample overclocks differently, that's why our results here can only serve as a guideline for what you can expect from your card.



The overclocks of our card are 940 MHz core (4% overclock) and 1085 MHz Memory (9% overclock). To be honest I was very disappointed by this overclock. Based on the early information available I expected something in the 1000 MHz+ range on core with all the overclocking features this card offers.

I did some additional testing with increased voltage. The HD 4890 reference and EAH4890 TOP both default to a 3D GPU voltage of 1.312V, the PowerColor 4890 PCS that we tested a few days ago runs at 1.5V.

At 1.312V the EAH4890 TOP does 940 MHz as mentioned above. With a voltage increase to 1.4V I reached a stable frequency of 995 MHz, and with an additional 0.1V, the card ran up to 1020 MHz. I asked one of our forum members (thanks MRCL) to run some testing on his retail reference HD 4890. At 1.312V he reached 945 MHz, with 1.4V he could run up to 975 MHz.

Based on these numbers I would say that the ASUS cooler and PCB design improves overclocking in regions where other cards are limited by heat or voltage. For the general user however this is of no use since he won't be tweaking his card all day. For the seasoned overclocker the card offers some additional OC potential but it is not that much - 20 MHz make no difference in games. The hardcore people will use a liquid nitrogen/dry ice pot anyway so there is no benefit from the ASUS cooler, cherry picking from a large number of cards will clearly net better results.

Overclocked Performance

Using these clock frequencies we ran a quick test of Call of Duty 4 to evaluate the gains from overclocking.


The actual 3D performance gained from the "normal voltage" overclocking is 4.7%.

Temperatures

Temperatures are very low. Especially idle seems unnecessary low which suggests there is some huge potential for quieter fan settings.