Looks like your running the system hard.
I was reading this again and noticed you have different settings in your BIOS. The C.I.A.2 you have full throttle
while theres is Disabled
In other words, you can hit pretty good overclocking results on Gigabyte GA-P35-DS3R by simply changing the bus frequency and raising the Vcore and Vmem. This way we managed to reach 505MHz bus frequency.
And this is what the BIOS Setup settings looked like to ensure that the mainboard would run stably at this speed: