GT 240 and double precision

Accelerated Computing CUDA CUDA Programming and Performance
1

Hello everybody,

Did anyone know if the GeForce GT 240 support double precision?, if not, can anyone recommend me a graphic card, no more expensive than 150.00 €, that support it?

Best regards

2

You need compute capability 1.3 (or even better: 2.0) for double precision.
http://developer.download.nvidia.com/compute/cuda/2_0/docs/NVIDIA_CUDA_Programming_Guide_2.0.pdf

The GT240 has compute capability 1.2
http://developer.download.nvidia.com/compute/cuda/3_1/toolkit/docs/NVIDIA_OpenCL_ProgrammingGuide.pdf

Early CUDA-enabled GPUs did not provide double-precision support. The most recent GPUs, such as the GTX 260 and GTX 280, do support double-precision. However, by default the CUDA compiler does not use double-precision arithmetic.
https://www.cs.virginia.edu/~csadmin/wiki/index.php/CUDA_Support/Enabling_double-precision

If your GPU has compute capability 1.3 then you can do double precision. You should be aware though that 1.3 hardware has only one double precision FP unit per MP, which has to be shared by all the threads on that MP, whereas there are 8 single precision FPUs, so each active thread has its own single precision FPU. In other words you may well see 8x worse performance with double precision than with single precision.
Compute Capability 2.0 devices (aka Fermi) have much improved double-precision support, with performance only half that of single-precision.
http://stackoverflow.com/questions/2816992/double-precision-floating-point-in-cuda

Kind regards,
Wouter.

3

The GTS450 is probably the only current card with double precision support in that price range.

Telsa compute capability 2.0 devices have a double:single floating point throughput ratio of 1:2. All the consumer Geforce Fermi cards either have 1:8 or 1:12 double:single performance ratios.

4

There are also the GT 430 and GT 440 (released a few days ago) which can do hardware double precision for less than US$100, although they are pretty underpowered.

5

Hi all, according to what I have and what I need I decide to buy a GT 430, thanks a lot for your comments.

Best regards.