this ar my bios settings for x5690 @ 4.6Ghz,If not mentiond its on auto or on stock
R.I.P  x5690 kiled my chip while running +5g
 
CPU
 
C1E : disabled
MAX cpuid : disabled
Intel VR : enabled
Intel VT-D : enabled
Corency support : disabled
Execute-disable BIT : enabled
Active core : ALL
A20M : disabled
Speed step : disabled
C-state tech : disabled
Acpi T state : disabled
CPU : 200
PCIE : 100
CPU multi : 23
QPI link : full-speed
QPI frequency :
Memory frequency : DDR-1333
MCH strap : auto
CPU uncore : auto
 
Voltages:  for dayli use i don't recomand to go above  1,35 - 1,375 for vtt and 1.42 vcore
 
Vdroop control : whitout vdroop
Boot Vcore : 1.41875v
Eventual Vcore : 1.41875v
Boot cpu0 VTT : 1.35v
Eventual VTT : 1.35v
Dimm voltage : 1.65v
 
Signal tweaks
QPI 0 : -85
QPI 1 : -16

ok, thanks. I only have x5650s and killing them is not an option for me. Would would it take for me to hit around 3.6Ghz? 4 would be great but I need to ensure it stays stable. This machine is used in my business for video editing and I can't afford for it to crash while it's doing render queues etc. Appreciate your reply btw!

I have two Corsair Hydro Series H80 on the processors. Everything else is air cooled. If I use those values to try and get 3.5Ghz do I just leave all the other things on auto?

I really am new to overclocking but can someone recommend a guide or something to read so I can at least start to get an idea of what all the values actually do?

Skulstation2 I'll try your numbers over the weekend and see how I get on.

Thanks, M.

166 bclk with everything else on auto (1600 mch strap) should just work. Much higher with dual 6-core CPUs and 12 DIMMs, and if you think it's stable it only means you haven't stability tested hard enough.
 
Westmere 6-core Xeons s are good for about 4.1-4.2GHz with high end non-cryogenic cooling. Any higher will not be 24/7 stable. If you're going faster and you think it's stable it only means you haven't stability tested hard enough.
 
I run my X5690s at 4.0GHz, the machine is on 24/7 being a multi-seat virtualized workstation.
 
Once it's working with bclk=166 and everything else on auto (with X5650s, with faster CPUs you will need to reduce the multiplier to ensure they do not exceed 4GHz, possibly less depending on how good your heatsinks are) you should be able reduce various voltages, but this you will have to test yourself to find the stability limits. Note that turbo-boost will push the X5650s beyond their reported clock speed, so 166bclk is going to be sufficient to get you to your intended effective clock speed target.