Radeon HD 4890: Overclocking
Geforce GTX 275: Maximal OC frequency at maximal fan speed [Source: view picture gallery]
Up to now we have three HD 4890s, all of which have AMD's default design: The Sapphire Radeon HD 4890 (default frequencies), the Asus EAH4890 (default frequencies) and the His Radeon HD 4890 (OC version with 900/1,000 MHz). Although there have been several reports of cards running stable at 1,000 MHz core clock speed, we can't confirm those rumors with these three cards. All of them quite over 950 /1,100 (2,200) MHz. Nevertheless the results are quite good given the fact that the best samples of the HD 4870 (RV770) quit at about 850 MHz.
AMD leaves the decision concerning the power supply (almost) fully to the board partners. All of our samples had two 6-pin power connectors but there are said to be versions with one 6-pin and one 8-pin connector, too. The latter one makes a higher TDP possible and thus paves the way for higher frequencies and voltages - the new cooling solution appears to be ready. We are waiting for more retail cards and will keep you up-to-date in the matter. Geforce GTX 275: Overclocking
Our Nvidia reference sample of the GTX 275 offers similar overclocking capabilities as the other GTX 200 cards. To check the maximum re manually set the fan speed to 100 percent. This way our sample runs 3DMark 06 with 702/1,566/1,296 MHz (default: 633/1,404/1,296) and is almost 10 percent faster than before. As soon as we had the chance to test several retail cards we will rate the general overclocking capabilities of the GTX 275.