Currently, I learn deep neural networks on my CPU (i7-6700K) using TensorFlow without AVX2 enabled. The networks need about 3 weeks to be learned. Therefore, I am searching for a (cheap) way to speed up this process. Is it better to compile TensorFlow enabling AVX2 or to buy a cheap GPU like the GeForce GTX 1650 Super (about 180€ and 1408 CUDA cores)? What is the estimated performance gain of using a cheap GPU?
 Cheap compared to current top edge GPUs.