woth mojave I do all the possible tests on SATA disk , on SSD disk...in APFS , in HFS....no change.
the best way is waiting...
SIERRA HIGH (non last updates , because are wrong like mojave drivers...)
work perfect with 660 , in native mode, and CUDA dirvers are perfect.
what softwares or special thing you lose , with mojave ? NOTHING!!!
also..mojave have few incompatible with plugs and softwares .
wait how long? long..mojave have somthing specila really important, more of sierra high , or...new softares update are no more supported for sierra high.
This can happen with apple softwares , but after long time waiting, today is come the new final cut pro x 10.4.4 , and still work also on sierra high...
like all the anothers software apple and not.
in this time..."MEABY"... nvidia update the CUDA dirver...
MEABY apple fix the bug in internal NVIDA DRIVER (for 5xx, 6xx, 7xx users!!)
MEABY apple/NVIDIA release a new WEB DRIVERS... for us and all the another 9xx, 10xx nvida users...
if not, and in time mojave is really better and with new software , no work any more in sierra high...ok is time to take a RX video card...withe the "litte" different , than now...a sapphire rx 580 8gb you pay around 250 euro... in few months, sure 150 !