GPGPU: Bitcoin, Litecoin, LuxMark, And RatGPU
The following disciplines don't capture every aspect of general-purpose computing (there are still Photoshop, WinZip, and video editing benchmarks in our suite that we weren't able to run). Nevertheless, they give us a good idea of how Maxwell improves upon the Kepler architecture, and where Nvidia now sits relative to AMD.
Although the company isn't going into depth on the improvements it made, we know that Maxwell handles hashing far better than Kepler, which is reflected by its victory over the GeForce GTX 680 and 770. At least in BTC mining, however, GeForce GTX 750 Ti still gets hammered by Radeon R7 260X and some of AMD's other more mainstream cards.
Of course, Bitcoin isn't the only cryptocurrency reliant on hashing. MaxCoin, for example, is a member of the SHA3 family, and it's supported in the latest version of CudaMiner. Curious as to how GeForce GTX 750 Ti sizes up to 650 Ti, we ran the following SHA2-based test in Sandra 2014:
There are big gains to be had from DirectX's Compute Shader, but throughput via CUDA is downright phenomenal. It's probable that Maxwell improves some of the integer operations that were slower on Kepler. Hopefully Nvidia opens up more about what the new architecture can do.
Bitcoin mining is almost irrelevant to CPU and GPU miners these days, if only because it's impossible to compete with dedicated ASIC- and FPGA-based devices working so much faster. But at least for a short time still, Litecoins remain at least a somewhat viable option. The use of scrypt (a password-based key derivation function) in their proof-of-work algorithm, rather than Bitcoin's SHA-256, makes dedicated hardware more difficult to develop. So, GPUs still rule, even if increasing difficulties make the investment in equipment and power greater than current returns.
Historically, Nvidia's cards came up short against competing Radeons, which is why you see R9 290X boards selling for $700 and up. But the Maxwell architecture's improvements allow the 60 W GeForce GTX 750 Ti to outperform the 140 W GeForce GTX 660 and approach AMD's 150 W Radeon R7 265, which just launched, still isn't available yet, but is expected to sell for the same $150. On a scale of performance (in kH/s) per watt, that puts Nvidia way out ahead of AMD. Today, four GM107-based cards in a mining rig should be able to outperform a Radeon R9 290X for less money, using less power.
LuxMark is another bastion for AMD, where the compute performance of its GPUs typically dwarfs competing Nvidia cards. The Radeons are so much faster, in fact, that Nvidia typically avoids addressing our results, stating only that it doesn't optimize for compute workloads on its gaming cards.
Again though, for a 60 W board, the GeForce GTX 750 Ti does pretty well. It still falls behind the Bonaire-based cards in its price segment. But compare its score of 943 to the GeForce GTX 580's 893. That's an almost-250 W former flagship!