Compared to Asus Mainboards with the same Chipset
ASUS M2N-MX and M2V-MX etc... Series (not low coast)
with ASRock (little bit cheaper) using same via chipset:
ASROCK ALIVENF6P-VSTA and ALIVENF6G-VSTA etc...
My overall performance with different Graphic boards is by Asrock better. The tuning options in the bios is by asrock ami bioses more extended. I will not say low coast is less good, sometimes it can beat high price brand names.
Did you check your bios setting for the graphic card?
Yes, of course I've checked. Anyway the bios does not have graphic card specific options. It only allows to enable/disable the embedded vga. No options for the PCI-E one (apart from the boot priority for vga cards).