Help for overclocking Q6600

Well I have managed to overclock to 3.5ghz but if I try to go past this number my computer wont boot....Im new at overclocking and my boyfirend told me I did a decent job but I dont think I did ..If anyone has any tips to help me i'll post my computer and my extreme tweaker specifications below.

Q6600 3.51ghz
Asus P5E motherboard X38 chipset
Crossfire HD3870 X2
4gb DDR 2
ATX 750 W supply
Windows vista ultimate

Heres my extreme tweaker

Ai overclock tuner - Manual
CPU ratio control - Manual
ratio CMOS setting - [9]

FSB frequency - [390]
FSB north bridge - [400Mhz]
PCI express frequency - [100]

DRam frequency - Auto
DRam command rate - [ 2T ]
DRam timing control - Manual

4 - 4 - 4 - 12

all the rest down about ram is on Auto

Ai clock twister - [Strong]
Transaction booster - Auto
VCORE voltage - 1.50 V
CPU PLL voltage - 1.66 V
FSB termination voltage - 1.20 V
DRAM voltage - 1.50 V
North bridge voltage - 1.47 V
South bridge voltage - 1.05 V



At these setting my computer is stable and doesnt overheat,
But if anyone could give some tips on what to change so i can go over 3.5ghz
or even tips on how to improve what im running atm would be much apreciated =D
Thank you for replying =)

I'm assuming "DRAM voltage" is the ddr2 voltage. If so, I think 1.5v is really low for memory. Isn't the default voltage 1.8v? I think upping the ddr voltage should help,

The DRAM voltage was my first thought as well.

Also, have you made sure to turn off any speed stepping features om the board?

By the way, what is the speed stepping features on a ASUS called, or where should I look to turn it off?

First, I would try playing with memory settings. See what the manufacturer specifies for your memory. May need more voltage. Also, while you're trying to increase the FSB, loosen the timings on the memory (I would start at 6-6-6-18) I see you have frequency of the DRAM set to auto also. I would set that manually, so you can control the memory dividers. Keep it at 1:1, there's no need to go higher than that IMO. Also, 3.51 is still a VERY GOOD OC on air, and nothing you should sneeze at.

^_^ alright thank you i'll try that and see if it works =D