The GPU acceleration feature has been noted to have some problems with it. If you look at the performance tab in the Lightroom preferences there is a link to get more information. Check that link to determine if your graphics card meets the specifications. Even if it does, that is no indicator that using GPU acceleration will benefit you. Those who are seeing the greatest impact from GPU acceleration of those using Macs with high-resolution retina displays.
Just read Eric Chan's post and his explanations explain what I am experiencing.
Wish I could predict what sort of a performance boast a new graphics card would provide. Something like the Nvidia GTX 960. Running Windows 7 Pro, Intel i7 4690 at 4.0mhz, 32 gb ram on a 1tb Samsung EVO SSD.
KB don't bother upgrading. I have a 4770k, GTX 970, 16 GB ram and 2 500 GB Crucial MX200 in RAID 0 and with GPU acceleration on it still is slow. Adobe has major issues with this from what I'm gathering GPU acceleration on actually doesn't use the GPU at all and actually taxes your CPU more with it being on!
Thanks amandajm13!!! I kind of guessed that after further reading. Going back to LR 5.7.