AMD Radeon HD 7870 and 7850 Specifications and Review

7870 GHz Edition

 7870 and a 7850. Both are built on the 7870 reference design, so the cards are functionally identical except for the configuration of their respective GPU and the number of PCIe power sockets present.

For retail cards this will be very similar to the 7700 series launch, with partners doing semi-custom cards right away.

In fact among the list of cards AMD sent us only Club3D will be using the complete 7870 reference design, while everyone else will be using the reference PCB along with their customary open air coolers. The 7850 will be even more divergent since AMD actually has a different, shorter reference PCB for these cards.

Consequently our 7850 has very little in common with retail 7850s when it comes to their construction.the 7870 reference design is effectively a smaller version of the 7970 reference design. Here AMD is once again using a blower design with a slightly smaller blower, shrouded in the same hard red & black plastic as with the 7900. Underneath the shroud we find AMD’s heatsink, which utilizes a copper baseplate attached to 3 copper heatpipes, which in turn run into an aluminum heatsink that runs roughly half the length of the card. This is fairly typical for a blower design for a sub-200W card, but again almost all of the retail cards will be using a completely different open air design.The 7870 PCB itself runs 9.5” long, with an additional .25” of shroud overhang bringing the total to 9.75”. Our card is equipped with 8 5GHz 256MB Hynix GDDR5 memory chips, the same 5GHz chips that we saw on the 7700 series.

Radeon 7850

For the 7870 power is provided by a pair of 6pin PCIe power socket, while the sub-150W 7850 uses a single socket. Both cards feature a single CrossFire connector, allowing them to be paired up in a 2-way CrossFire configuration.

	Radeon HD 7870	Radeon HD 7850
GPU	Picairn XT	Pitcairn Pro
Process	28nm	28nm
Engine Clock	1000 MHz	860 MHz
Prmitive Rate	2 prim / clk	2 prim / clk
Stream Processors	1280	1024
Compute Performance	2.56 TFLOPS	1.76 TFLOPS
Texture Units	80	64
Texture Fillrate	80 GT/s	55.0 GT/s
Raster Operating Units	32	32
Pixel Fillrate	32 GP/s	27.52 GP/s
Z/Stencil	128	128
Memory Clock	2 GB GDDR5	2 GB GDDR5
Memory Type	1200 MHz	1200 MHz
Memory Data Rate	4.8 Gbps	4.8 Gbps
Memory Bandwidth	153.6 GB/s	153.6 GB/s
Typical Board Power	175 W	130 W
AMD Zero Core Power	< 3 W	< 3 W

Meanwhile for display connectivity AMD is using the same configuration as we’ve seen on the 7900 series: 1 DL-DVI port, 1 HDMI port, and 2 miniDP ports. Interestingly, unlike the 7900 series and 7700 series there is a set of pads for a second DVI port on the card, and while AMD doesn’t make use of them at least one XFX card will. The 7800 series as the same display configuration options as the 7900 series though, so while it can drive up to 6 monitors it can only drive 2 TMDS type displays at once, and if you want to drive a full 6 monitors you’ll need a MST hub. Tech Spot

3DMark 11 Product Positioning	3DMark 11 Entry Preset	3DMark 11 Performance Preset	3DMark Extreme Preset
AMD Radeon HD 7870 GHz Edition	10550	6751	2059
AMD Radeon HD 7850	8935	5532	1653
NVIDIA GeForce GTX   570	8954	5749	1837
NVIDIA GeForce GTX   560 Ti	7776	4754	1510