there is a win 8 driver. http://www2.ati.com/drivers/firepro/9.003.3-WHQL-x32x64-151862C.exe
from the page http://support.amd.com/en-us/download/workstation/certified
selecting the 3750 card and win8 X64 os. there is no win8 X32 driver but there is a 64 driver.