GPGPU: Floating-Point Performance
Single-Precision, Good. Double-Precision, Bad.
Nvidia's mainstream Kepler-based GPUs offered double-precision compute performance that was 1/24 as fast as its FP32 math. Maxwell is ever worse at 1/32. Of course, that's purely theoretical until we double-check it with real-world benchmarks.
The Folding@Home benchmark is particularly good for comparing graphics cards under OpenCL. We had to do without CUDA-based numbers this time around because the Maxwell-based card wasn't properly recognized. This is simply something we'll have to put together later.
How big is the difference between single- and double-precision, really? Our benchmark results indicate a 8:1 ratio between them on Nvidia's GeForce GTX 750 Ti (Maxwell). That's quite a bit weaker than the GeForce GTX 760's (Kepler) 4:1 in this metric (Explicit Solvent).
But GM107's comparatively strong single-precision performance is what sticks out; it's able to compete with much more potent graphics cards. By the time you get to its double-precision numbers, compute throughput ends up just below where we would have expected it.
Single-Precision Benchmarks (SP)
Double-Precision Benchmarks (DP)
We're not sure what to think about GM107's increasingly hobbled FP64 capabilities. You can either say double-precision performance is really bad, or the single-precision numbers are really good. Regardless, at the end of the day, artificial limitations meant to prevent cheap desktop cards from being viable workstation parts are no less irritating.
I'm pretty sure you meant to type "video cards" on page one there. Cheers.
Don't take this as fact, but the drivers look newer for the Zotac card than the others, possibly just a bug with the older drivers? The cards are advertised as having 640 shaders anyway.
Also weird, the GPU-Z screenshot is taken with Windows 8, whereas the Gigabyte and MSI cards are on Windows 7. The mystery continues...