“Serious gaming starts here.” With that slogan AMD launched its Radeon HD 7850 and 7870 graphics cards in March. It's actually surprisingly apt, as the HD 7870 can handle pretty much any game in Full HD resolution (1920x1080), albeit not always at the highest settings.
Both the 7850 and the 7870 are based on the Pitcairn GPU, the middle one of the three Southern Islands GPUs. This Pitcairn consists of 2.8 billion transistors and 20 compute units, which results in 20 x 64 = 1,280 shader units. That's twice as many as the Cape Verde of the Radeon HD 7750 and HD 7770. The connection with the memory is twice as fast as well, as Pitcairn has a 256-bit memory bus.
On the 7870 GHz Edition all of the shader units on the Pitcairn GPU are enabled, and the GPU runs at 1 GHz. The card has 2 GB GDDR5 memory running at 1200 MHz. The TDP is 175 watts, and on the back there are two 6-pin PEG power connectors. The card comes with a single Crossfire connector so you can combine two 7870s. Connectors consists of one dual-link DVI, one HDMI and two DisplayPort 1.2.
The Radeon HD 7850 looks identical to the 7870, but there are differences. The GPU has 1024 of the 1280 shader units enabled, which is 20 percent less. The clock frequency has also been reduced to 860 MHz, but the 2 GB of RAM remains the same along with its clock frequency. The Radeon HD 7850 has a TDP of 130 watts, so only one 6-pin PEG connector is required. It also has a single Crossfire connector and the same number of monitor connectors as the 7870.
Just like we recently reviewed and compared seven video cards based on the Radeon HD 7750 and 7770, we are now comparing nine graphics cards based on the 7850 and 7870. We're most interested in their mutual differences. If you want more in-depth information about the technology, you can read our original review of the Radeon HD 7000 series.