|First you have 800MHz DDR2 (400MHz frequency x 2 'Double Data Rate')|
Unfortunately you have no 'Head Room' for overclocking on that combination since you have a CPU that is 1333FSB and a motherboard that supports only up to 1333FSB and your CPU's multiplier locked at a maximum or 8.
Your processor: 333.3 MHz frequency x 8 (multiplier) = 2667MHz = 2.67GHz
Your FSB: 333.3 MHz frequency x 4 = 1333FSB
Your memory should be running 333.3 x 2.0 = 667MHz DDR (underclocked) for a Ratio 1:1
Your board is probably running your memory at it's max setting 333.3 x 2.4 = 800MHz DDR2 (faster but not considered optimal by many)
IF your motherboard supported 1600 MHz FSB (it does not) you could have used 400MHz frequency x 8 = 3200MHz = 3.2GHz but you cannot. Had your CPU been one of the lower frequency duo or quads you could have done a little better (my E7500 is one of those so it OC's to 3.54 on a 1333FSB board, but my E8200 only reaches 3.2 on a 1600FSB board for the same reason. Many 'better' 1600FSB boards can go higher, but the tweaking gets trickier with chipset voltages and other things, but not usually on 'lesser' boards with 1333FSB).
You have to be a little bit crazy to keep you from going insane.