AOpen will soon introduce new motherboards namely AX4C MAX, AX4C Pro, AX4SG Max and AX4SPE Max with a front side bus of 800MHz based on the new Intel Canterwood i865 and Springdale i875 chipsets. They do however provide a new BIOS file that allows you to use the upcoming 800Mhz FSB Pentium IV processors on their existing i845GE/PE motherboards. Anyone with knowledge about overclocking should be aware that the relationship between RAM frequency and CPU/FSB is closely related to each other, and they are running in a brilliant and fixed ratio. For example, while you are running Northwood-2.8G with 533Mhz system bus, the FSB on your motherboard is running correspondingly with a speed of 133MHz; at the same time, the DDR333 to go with your system is practically running at 166MHz. After the math, we come out with a ratio of 4:5 (133MHz : 166MHz) between FSB and RAM. These components are running in such a harmonious way perfectly - if you do not plan to do any over-clocking over them. Here comes the problem, but what if you want to adjust your FSB to 200MHz for supporting Intel's latest CPU with 800MHz? After simple calculating, it shows that you got to squeeze your RAM up to DDR500 to cope with the system! Apparently, the chance of achieving DDR500 is too remote and slim up to date. But is it impossible? Why don't we turn things around? What if I could modify the ratio of 4:5 ratio, and still forcing my RAM to run in a normal speed? Does it mean that overclocking superb 800MHz is achievable then? You are right! Now, AOpen RD has managed a special way to adjust ratio and cheat chipset without modifying hardware. All the complex setting and procedure are done by a new BIOS version. Simply follow below steps and you can enjoy the racing speed of 800MHz steps earlier. Necessary steps for setting up FSB800 for 845GE/PE motherboards: Step 1: Before making any adjustment in the BIOS for 800MHz supports, it is a MUST to download the latest BIOS from our website: http://club.aopen.com.tw/downloads/ 
Step 2: Make sure it is DDR400 memory used.
Step 3: Power on and enter the BIOS, setting CPU FSB=200MHz.
Step 4: Set the DRAM frequency ratio to 2, so that the DDR runs under the 200*2=400. Step 5: Press F10 and save, then you will find the POST screen with FSB800. For further information about the setting of FSB800 in BIOS, please refer to our technical site: http://english.aopen.com.tw/tech/report/overclk/mb/FSB800_0.htm