The BIOS on the DFI GF9400 T2RS is an Award BIOS that has been modified by DFI to be their own special thing. For many the way that DFI adds in overclocking features is worth all of the other hassles and headaches.
Other than a few extra features like BIOS Genie and CMOS Reloaded, the DFI implementation of the Award BIOS is pretty standard. Below you can see the options available for overclocking as well as the pre-set overclocks available in the DFI BIOS.
I ran into a small issue with the DFI GF9400 and it is one I have run into before. When I was working on the stable OC for testing I had a couple of times where the board would not post. For some reason the normal means for resetting the BIOS would not work at all. I had to completely power down the board (remove the PSU connectors) and pull the battery. This was the only way the BIOS would reset. The DFI BIOS is very hardy, but at times this can become a real inconvenience.
Overclocking with any DFI board is an exercise in patience. They really do give you a ton of options. However, I think that for this board the overclocking tools are probably overkill. The E8400 I used has been up to 4.2GHz on water (with a chiller), but as I was only using air and I did not want to push too much voltage through the system.
I ended up with a stable overclock of 3.6GHz; this being with a 400MHz FSB x 9. Memory was down clocked to 800MHz to get this as for some reason when I pushed it up to 1066 or higher the IGP would begin to have problems and would lock up the system.
You can see the validation here.
As all overclocking results are dependent on the hardware you use, your results may vary. Results of our overclocking tests are included in the performance section with the stock scores.
Important Editor Note: Our maximum overclocking result is the best result we managed in our limited time of testing the motherboard. Due to time constraints we weren't able to tweak the motherboard to the absolute maximum and find the highest possible FSB, as this could take days to find properly. We do however spend at least a few hours overclocking every motherboard to try and find the highest possible overclock in that time frame. You may or may not be able to overclock higher if you spend more time tweaking or as new BIOS updates are released. "Burn-in" time might also come into play if you believe in that.