|"if the RAM speed is memory freqency then its 833"|
That's not the frequency, that's the DDR rating.
"my DRAM freqency is ~415 MHz"
There you go, 415MHz is the frequency. I'm guessing you have DDR2-800 & you've already increased the CPU frequency?
"FSB:DRAM in CPU-Z Its 3:5"
OK, based on the above, you've apparently increased the CPU frequency to about 250MHz? If you didn't touch the CPU multiplier, the CPU should be running at approx 3.0GHz. However, with the 3:5 ratio, the RAM is running out of sync & you're taking a performance hit.
I'll download the board manual, check the BIOS chapter, then get back to you.