Building my GPU rig. Still haven't settled on a graphics card just yet. It seems the "standard" GPU of choice is an R9 280X, or similar. It is stated Radeon GPUs get better perfomance overall compared to NVidia based devices. However, in terms of a rough comparison, I did some googling to see how they compare
512 CUDA cores vs 2048 Stream processors (I realize they don't directly compare)
1.3 GHZ vs 1 GHZ clock speed
6 GB GDDR5 vs 3 GB GDDR5 memory
177 gb/s vs 288 gb/s memory bandwith
1.85 ghz vs 6 ghz memory clock speed
225 Watts vs 250 watts power consumption
It's really strange to compare the two. More memory, slower and less bandwidth, but a higher clock speed?https://en.bitcoin.it/wiki/Why_a_GPU_mines_faster_than_a_CPU#Why_are_AMD_GPUs_faster_than_Nvidia_GPUs.3F
Scrolling down to the explanation of why AMD mines faster than Nvidia is because in the SHA256 algorithm, many shift instructions are used. Since ethash makes use of Kekkak, I decided to check what it mainly uses, which is XOR. There's still two shift instructions, one of which might require many iterations to shift. AMD fires back though with a single rotate-wherever bit align instruction. Perhaps the extra .3 GHZ could make up for this?
I'm rather unsure of whether or not the M2090 is worth the hashes/$ for $145 on ebay, whereas I could spend about $20 more to get something that can output an average of 20 MH/s.
...Then again, I read someone's benchmarks of their Quadro 4200, which has 448 CUDA cores @ 1.6 GHz, and 4 GB of GDDR5 memory @ 173 gb/s, and managed to pull around 19 MH/s. Both devices are, of course, using CUDA 2.0, and are Fermi-based architectures, so it's logical to conclude that if the 4200 can use the mining software, so can the M2090
So... slightly slower GPU with more cores, twice the memory, a slightly faster memory, and less power consumption, *MIGHT* prove advantageous over an R9280X.
I could experiment to see just what it can do. Returns within 30 days for the tesla are accepted if it doesn't work out
What do you miners think? Deal or no deal?