Cant get E6400 past 3.36 gig stable

[PANFACE]

Which way next??

My system (and running at)

E6400@3.36
Gigabyte 965P-DS3P
Corsair ddr2 800
GeForce 7900GS
Thermalright SI-128 Heatsink
Enermax 420w PSU

420FSB
1.41V
MEM 840freq
2.0V
5-5-5-15 timing

At these settings it will run a fractal test for 12 hours before I stop it,
It ran Prime 95 for 4 hours before I stopped it but Orthos Beta for only a couple of hours before it failed.
Temps are good, Speedfan CPU Temp reading is around 30/35 Idle and 45/50 loaded using Prime 95.
Tried upping the CPU V to 1.45 in the Bios (read 1.44 in Easy Tune) and it failed Prime 95 in minutes.
Messed around with MCH OverVoltage and FSB OverVoltage a bit but it didn’t seem to help so I set them back to AUTO.
I’m still new to all this so here’s what I assumed….. the system would still be as stable with the extra voltage to give some extra juice to push for 3.4Gig. (Obviously NOT)
Is it possible to over vault and make a system unstable?? :?
Also when do MCH OverVoltage and FSB OverVoltage come into play :? ??
I've hit a bit of a wall and would welcome any input to get moving again.
Cheers,
Panface.

 

[PANFACE]

Thanks for the advice beerandcandy, can you enlighten me any about
MCH OverVoltage and FSB OverVoltage?

Cheers.

 

[PANFACE]

Thanks again

 

[jamiepotter]

That sounds like a pretty normal upper limit to your chip, to be honest. Maybe you can't get any higher because it's not going to go any higher? If it were 2800mhz, I'd think something was amiss, but 3.36ghz is a pretty reasonable OC, I'd say, given what is a _fairly_ good CPU heatsink. You're not going to get much more out of it, whatever you do.

Tom's Hardware got pretty much the same OC, and they're hardly muppets:
http://tomshardware.co.uk/2006/10/10/cheap_thrills_uk/