Q: If I use Conroe 1066-CPU on 775Dual-VSTA. What kind of memory should I use?(2006/5/24) A: If the BIOS version is P1.00, we recommend to use DDR400 and DDRII667 memory module; however, BIOS version is P1.10 and later can support DDR400, DDRII533 and DDRII667, so if you will use DDRII533 modules on your system, we suggest you update bios to P1.10 or later version.
https://www.asrock.com/mb/download.asp?Model=775Dual-VSTA#bios