Q: I'm using P4i45PE now. How do I run FSB 800 MHz correctly?(2003/7/9) A: 1.Please use Intel® FSB 800 MHz CPU for your system.
2. Please set FSB jumper in pin 2-3 (Test)
3. Please install one DDR400(PC3200) in slot 1.
DDR SDRAM requires CL=2.5 or CL=2.
Please also refer to P4i45PE memory support list.
https://www.asrock.com/mb/memory/P4i45PE.pdf