1408 SPs for HD 7870 and 1280 for HD 7850
AMD is planning to launch its mid-range HD 7800 series cards based on the Pitcairn GPU sometime in March, or according to our sources, the first week of March. There will surely be a card or two at this year's Cebit show that kicks off on March 6. Expreview managed to score some details regarding the Pitcairn cards and it appears that we are looking at three different SKUs, the Radeon HD 7870, and two Radeon HD 7850 cards with either 1 or 2GB of memory.
The specifications of the fully enabled Pitcain based HD 7870 include 22 Graphics CoreNext compute units, or simply 1408 stream processors, 88 TMUs and 24 ROPs. The Radeon HD 7870 will ship with 2GB of GDDR5 memory paired up with a 256-bit memory interface. The HD 7870, at least the reference ones, should be set to work at 950MHz for the GPU and 1375MHz (5.5GHz effective) for memory.
The Radeon HD 7850 on the other hand has two GCN CUs less, for a total of 1280 stream processors, 80 TMUs and 24 ROPs. This one will be available with either 1 or 2GB of GDDR5 memory paired up with the same 256-bit memory interface. The HD 7850 should end up clocked at 900MHz for the GPU and 1250MHz (5.0GHz effective) for the memory.
There has also been talk regarding the Radeon HD 7890 SKU that could be based on the highly crippled Tahiti GPU, and should come sometimes after March.
You can check out the Expreview story here.