Temperatures, power consumption and noise levels

Although at lower RPM, fan on HD 4890 is very noisy at 60% of maximum RPM. Situation, in case of GTX275, is much better, because this kind of noise levels this card reaches at 80% from maximum RPM. Also HD 4890 reaches higher temperatures in IDLE than GTX275 so users that prefer quiet and cold graphics cards should avoid Radeon HD 4890. When it comes to power consumption things are slightly different. Both cards demand two 6-pin power connectors and have power consumption around 200W. ATI has slightly better specifications because its power consumption is for 30W lower than in case of GTX275. We actually measured power consumption of both cards and got slightly different values. GTX275 consumes for 20W more power than HD 4890.

Performance levels at default frequencies

Since we used optimal resolution for both graphics accelerators we also did all benchmarks with and without Anti Aliasing (AA) and Anisotropic Filtering (AF). We deliberately made even number of benchmarks so real possibility of tie results is, actually, possible. Interestingly situation is tie in case of default frequencies and no AA and AF. With 8xAA and 16xAF situation is drastically different in favor of HD 4890. Radeon HD 4890 is faster in amounts from few percents to significant amount.

Overclock possibilities

Despite the fact that ASUS stated on the packaging of GeForce ENGTX275 that ultra-quality components were used, overclock wasn’t too good. We achieved 660MHz for GPU and 1524MHz for Stream Processors, while memory achieved, respectable, 2.5GHz. Performances showed improvement but not in amount that we wished and expected. In this category Radeon HD 4890 also won. When we raised voltage from 1.3125V to 1.4V GPU reached 1GHz which is great result. Memory stopped at nice, but not so great, 4.64GHz (1160MHz x 4).

Overclock Performances

In this category Radeon HD 4890 showed its true face, while GTX275 remained reserved. Although these two graphics cards were tied when AA and AF were not used, situation has significantly changed and ATI is leading because of its great overclocking potential that is put to good use. In situations where HD 4890 slightly outperformed GTX275, difference when both cards are overclocked, is now even greater. We must mention that we overclocked both cards after long overclocking sessions just to reach maximum overclock paired with tolerable fan noise. So these results are for both cards set for 24/7 overclock.