We were disappointed with the Radeon HD 4850’s high power consumption at idle, though it was under control under load. Let’s see how the Radeon HD 4870 did in that department.
Unfortunately, the Radeon HD 4870 posted even higher consumption than the 4850 at idle – 22 W more overall, measured at the power supply. When just displaying the desktop ("at idle"), the card drops the GPU speed to 550. As soon as it displays 3D data, it increases the GPU speed to the nominal/maximum speed of 750. Compared to the Radeon HD 3870, the difference is 44 W, or a 40% increase in total consumption for the PC! So the poor power-management performance of the Radeon HD 4800 series has been confirmed. Another problem is that unlike the HD 4850, the Radeon HD 4870’s power consumption isn’t very economical while gaming. Here again its consumption was higher than the GeForce GTX 260’s. Performance-wise, that makes sense, but not in terms of the difference in number of transistors and the high-end process.