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Introducing the Radeon HD 6850 and 6870
Now that we're several thousand words into our review, let's talk about the new Radeon graphics cards. Here are the most relevant specs:

GPU
clock
(MHz)
Shader
ALUs
Textures
filtered/
clock
ROP
pixels/
clock
Memory
transfer
rate
Memory
interface
width
(bits)
Idle/peak
power
draw
Suggested
e-tail
price
Radeon HD 6870 900 1120 56 32 4.2 Gbps 256 19W/151W $239
Radeon HD 6850 775 960 48 32 4.0 Gbps 256 19W/127W $179

Both cards have 1GB of GDDR5 memory onboard, and AMD has chosen to de-tune the 6850 only by reducing the number of active SIMD engine/texture unit pairs from 14 to 12 and lowering clock speeds.

Notice the very nice prices in the table above. These cards amount to a major overhaul of the value proposition in the middle of AMD's lineup.

Peak pixel
fill rate
(Gpixels/s)
Peak bilinear
INT8 texel
filtering rate*
(Gtexels/s)
*FP16 is half rate
Peak
memory
bandwidth
(GB/s)
Peak shader
arithmetic
(GFLOPS)
Radeon HD 5830 12.8 44.8 128.0 1792
Radeon HD 6850 24.8 37.2 128.0 1488
Radeon HD 5850 23.2 52.2 128.0 2088
Radeon HD 6870 28.8 50.4 134.4 2016

At $179, the Radeon HD 6850 essentially replaces the weak-sister Radeon HD 5830, yet it has twice the ROP rate of that rather unfortunately crippled Cypress derivative, is based on a smaller board with more modest power consumption, and, well, we'll show you performance shortly. At $239, the Radeon HD 6870 supplants the Radeon HD 5850, yet the newer card costs less, has a higher ROP rate and slightly more memory bandwidth, with comparable specs otherwise.




Above are a couple of Radeon HD 6870 cards from XFX and Sapphire, both of which are available now, and both of which look to be based on AMD's reference design. 6870 cards require dual 6-pin auxiliary power connectors, and at 9.75" long, they should be considerably easier to cram into a case than the over-11" Radeon HD 5870. They're practically the same size as the Radeon HD 5850, though.



Pictured above is the reference version of the Radeon HD 6850, which has a single 6-pin power input and measures 9" long.




Right out of the gate, XFX is offering a verison of the 6850 based on its own custom board design that's a quarter-inch shorter than AMD's and rocks a Zalman-esque dual-heatpipe cooler. XFX says it's using higher-quality components to give its cards longer life and better overclocking headroom.

Unfortunately, both of these XFX cards are currently selling for 20 bucks above AMD's suggested price at Newegg, while other versions, like this Sapphire 6850, are priced in line with AMD's guidance. XFX may be able to command something of a premium thanks to its lifetime warranty and solid reputation for support, but $20 seems like a lot to ask.


From left to right: Radeon HD 5870, 6870, and XFX's custom 6850