Posts Tagged ‘CUDA 1.3’

GTS 240/250 : The return of GeForce 8800

Monday, July 27th, 2009

nVidia’s launched the GTS 250 months ago, based in fact on GeForce 9800GTX+ design (that is an overclocked 8800 inside!!!) and now the GTS 240 that is a G92b GPU from GeForce 8800 lineup.

I am happy to have a “real” GeForce 8800 to play with, but I wonder if consumer will pay twice their values for 2 years-old hardware repackaged?

For CUDA, I regret that nVidia is launching old hardware instead pushing CUDA 1.3 enabled devices, even with low clock or low frequency, because we all need CUDA 1.3 devices (shared Atomics, Double fp, twice register count … ) to write better CUDA or OpenCL software.

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Target Architecture

Wednesday, May 13th, 2009

CUDA is supported by 2 architectures : the 2 years-old GeForce 8xxx/9xxx/GT/GTS architecture and the new GTX architecture.

There’s finally few differences between the new GTX architecture and the old one, such as doubling the register number, and the coalesced memory access algorithm, the double (64bits floating point number) support, and few instructions.

Even on the first architecture, older GeForce 8800 (CUDA 1.0 architecture) may lack some features of the actual ones (or Geforce 9800/GTS250 as they were renamed :-( ), such as atomic operations. Cruel!

I will focus on what is known as CUDA 1.1 devices, such as formet GeForce 8800, 8600, 8500, any 9xxx or GT/GTS. They share the same general architecture and metrics, mainly differenciated by number of SP (Scalar Processors), frequencies, memory bandwidth (bus size & frequency) and naturally memory size.

I have one GeForce 8600M GTS, with 32 SP (Scalar Processors) on my laptop, and a GeForce 8800 GTS, with 96 SP on my home desktop, that is approximately 4X faster, due to increase in frequency as well as having more cores.

I plan to go for a GeForce GTX 260 (CUDA 1.3 device) if I am lucky on CraigsList or find a good sale, in the future, while staying compatible and optimizing for the CUDA 1.1 devices.

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