"I updated Mac OS today to High Sierra 10.13 from the App Store. Since my Hackintosh has Samsung 850 EVO SSD(s), my Apple file system was changed by the installer from HFS+ to APFS. No problems at all with the update; it took 41 minutes, just what the installer predicted. One expects to lose audio on a "Hack" whenever the OS is updated, and sure enough that happened. But "Toleda" has written a Terminal script that fixes that, which I applied per his instructions, and audio is now back. So far all is good. I have noticed no change in file retrieval times or anything else (yet).
The latest nVidia graphics web driver does in fact work fine with High Sierra, and my benchmark graphics programs report the same values (using the OpenGL API) as on Sierra 10.12.6 using HFS+. Results on "Heaven" and "Valley are below.
My Hackintosh uses an i7 6700 "Skylake" CPU, 3.4GHz, 65W TDP, and an nVidia GTX 1050 TI ("Pascal") graphics card.