Radeon HD 6870 vs GeForce GTX 645

Speed and memory

In our performance index the Radeon HD 6870 scores 2.4 and the GeForce GTX 645 scores 2.2, which makes the Radeon HD 6870 about 9% faster. That is a small gap, below what most people notice without a frame counter.

Both cards have 1 GB of video memory, so memory will not separate them.

In our estimates for popular games at 1080p on High, the biggest gap is in Red Dead Redemption 2 (6 against 5 fps), and the smallest is in Fortnite (31 against 29 fps). Games that are light enough to run above 200 fps on both cards show little difference at all.

Power and value

The Radeon HD 6870 is rated at 151 W and the GeForce GTX 645 at 65 W. With a mid-range processor that means a power supply of about 550 W for the first and 450 W for the second. A gap of 86 W shows up in heat and fan noise, and in your electricity use over a few years.

We do not have launch prices for both cards, so we cannot compare value. Check current listings for both.

Which one to buy

Choose the Radeon HD 6870 if you want the faster card, and it also has at least as much memory. It makes the most sense at 1440p and above, or on a monitor with a high refresh rate.

Choose the GeForce GTX 645 if the price gap matters more than the 9% speed difference, or if you want lower power draw and a quieter PC. Whichever you pick, check reviews for the games you play, because two cards with similar scores can differ in individual titles.