How many threads can I use at the same time ?

Accelerated Computing CUDA CUDA Programming and Performance
1

Hello!

I have a graphics card Nvidia GeForce 8400GS. I wonder how many threads can I use at the same time ? I am still learning about the Nvidia CUDA.

Many thanks for the quick reply and sorry for my English.

2

Per kernel invocation you can have a grid of 65535×65535 blocks with up to 512 threads each (fewer if your kernel uses many registers), so that’s up to 2,198,956,147,200 threads. Not all of them will actually run in parallel (instead there will be several waves of threads, a new wave starting when the previous one finished), but that is an implementation detail you don’t need to worry about.

The message to take away is don’t be afraid of using many (tens or hundreds of thousands) threads, GPUs just love them.