How much faster (approx) does Tensorflow run with a GPU?

Question

I have a Mac, and consequently have been running Tensorflow without GPU support (because it's not official yet). However, there are some hacked together impls that I'm thinking of installing... that is if the performance gains are worth the trouble. How much faster (approximately) would Tensorflow run on a Macbook Pro with GPU support?

Thanks

Answer 1

as a rule of thumb somewhere between 10 and 20 times - I've found just running the standard examples.

Answer 2

To give you an idea of the speed difference, I ran some language modelling code (similar to the PTB example), with a fairly large data set, on 3 different machines with the following results:

1. Intel Xeon X5690 (CPU only): 1 day, 19 hours
2. Nvidia Grid K520 (on Amazon AWS): 17 hours
3. Nvidia Tesla K80: 4 hours