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Dual AMD FirePro D500 with 3GB GDDR5
Configure your Mac Pro with dual AMD FirePro D500 GPUs for additional graphics memory bandwidth and processing power. Equipped with 3GB of VRAM each on a 384-bit-wide memory bus providing 240GB/s of bandwidth, each FirePro D500 GPU has 1526 stream processors delivering up to 2.2 teraflops of processing power each. The FirePro D500 supports fast double-precision computations, executing at one-quarter the performance of single-precision floating point rather than the 1/16 performance seen in the D300 and most consumer GPUs.
Dual AMD FirePro D700 with 6GB GDDR5
Tackle the most demanding 3D, 4K video, and scientific visualization problems by configuring your Mac Pro with dual AMD FirePro D700 graphics cards. Equipped with 6GB of VRAM each on a 384-bit-wide memory bus providing 264GB/s of bandwidth, each FirePro D700 GPU has 2048 stream processors delivering up to 3.5 teraflops of processing power each, for a total of 7 teraflops. The FirePro D700 supports fast double-precision computations, executing at one-quarter the performance of single-precision floating point rather than the 1/16 performance seen in the D300 and most consumer GPUs.
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So no idea what the difference in hash rate would be
![Smiley](https://bitcointalk.org/Smileys/default/smiley.gif)
![Huh](https://bitcointalk.org/Smileys/default/huh.gif)