For testing the AMD HD 7870 the following testbed was used:
Unfortunately we didn’t have a GTX 570 to test with, but as you’ll soon realize, the inclusion of the GTX 570 would have been moot since the HD 7870 is capable of going toe to toe with the GTX 580. Both the AMD HD 7950 and the Nvidia GTX 580 are running at reference (stock) speeds.
Drivers used were Nvidia 290.53 for the GTX 580 and Catalyst 11.12 for the HD 7950. The HD 7870 was using the beta 12.12 (8.895.5 build) which will be coming out soon as Catalyst 12.14.
Given that the HD 7870 was using a reference AMD heatsink, I wasn’t expecting much in terms of overclocking. However the new GCN certainly has some surprises up its sleeves. From the stock speeds of 1000MHz on Core and 1200MHz (4800MHz effective) Memory speeds, I was easily able to overclock the HD 7870 to 1200MHz on the Core. Anything higher, though, and I started to see severe artifacts on screen while running benchmarks.
Still, that’s an impressive 20% Core clock increase just on the reference design, I can imagine 3rd party cooling solutions where 1.3GHz could be achieved.
Interestingly, temperatures didn’t increase by much either. On stock speeds I was getting 28°C on idle and 69°C under full load. While overclocked, the temperatures increased up to 32°C on idle and 72°C under load. The fan noise remained consistently low throughout testing; lower than the HD 7970.
Benchmarks & Settings
Below are the details of how each benchmark was conducted with specific details of settings used. All of the below benchmarks were run at a resolution of 1920×1200.