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Last week we reviewed the excellent Sapphire HD7850 Overclock Edition and XFX have sent us their competing part – the XFX HD7850 Black Edition. This card features a even higher overclock, to 975mhz on the core with a custom two fan metal cooling solution. The big question, is this better than the Sapphire solution?
XFX and Sapphire have been head to head in battle for the last year, targeting various sectors with custom, overclocked graphics cards. The XFX HD7850 Black Edition looks a little more exciting than the HD7870 Black Edition we reviewed last week thanks to more daring core overclock speeds.
XFX are keen to highlight their ‘Ghost Thermal technology'.
What is this? Well XFX say “Through rigorous testing and analysis we have discovered the optimal thermal design that allows air to pass through the heatsink directly to the PCB and core components. Older enclosed designs often trapped the heat, creating a bottle neck at the exhaust, this can be remedied but at the cost of a higher fan speed which creates excess noise. Our design allows us to keep the fan speeds lower while allowing the heat to dissipate evenly throughout the card.”
| Product | AMD HD7970 | AMD HD7950 | AMD HD7870 |
XFX HD7850 BE |
| Core Clock speed | 925mhz | 800mhz | 1000mhz | 860mhz (975mhz) |
| Transistors | 4.31 billion | 4.31 billion | 2.8 billion | 2.8 billion |
| Stream Processors | 2,048 | 1,792 | 1,280 | 1,024 |
| Compute Performance | 3.79 TFLOPS | 2.87 TFLOPS | 2.56 TFLOPS | 1.76 TFLOPS |
| Texture Units | 128 | 112 | 80 | 64 |
| Texture Fillrate | 118.4 GT/s | 89.6 GT/s | 80 GT/s | 55.0 GT/s |
| ROPs | 32 | 32 | 32 | 32 |
| Pixel Fillrate | 29.6 GP/s | 25.6 GP/s | 32.0 GP/s | 27.52 GP/s |
| Z/Stencil | 128 | 128 | 128 | 128 |
| Memory Type | 3GB GDDR5 | 3GB GDDR5 | 2GB GDDR5 | 2GB GDDR5 |
| Memory Clock | 1,375mhz | 1,250mhz | 1,200mhz | 1,200mhz (1,250mhz) |
| Memory Data Rate | 5.5 GBps | 5.0 Gbps | 4.8 Gbps |
4.8 Gbps (5.0Gbps) |
| Memory Bandwidth | 264 GB/s | 240 GB/s | 153.6 GB/s | 153.6 GB/s |
XFX have opted for a generous 115mhz overclock on the core, raising the speed from 860mhz to 975mhz, this should have a dramatic impact on the overall performance. The 2GB of GDDR5 memory has been overclocked by 50mhz from 1,200mhz to 1,250mhz (from 4.8Gbps to 5.0Gbps effective).
