I have a Q9550 and I tried to overclocked it to past 4ghz but I'm stuck at 3.8ghz (447 * 8.5). My ex E8600 was able to reach 4.3 ( 4.4 was ok but a little too hot...

)
I cranked up all voltage in my mobo without exeeding the yellow zone but I can't get it stable.
the vcore was at 1.35 (tried 1.45....)
the fsb was 1.3 -1.4
nb 1.3(tried 1.5)
pll 1.68(tried 1.76)
ram 2.12(tried 2.2)
DRAM Frequency: ~1066Mhz
CAS# Latency: 5
DRAM RAS# to CAS# Delay: 5
DRAM RAS# Precharge: 5
DRAM RAS# Activate to Precharge: 15
RAS# to RAS# Delay : 4
Row Refresh Cycle Time: 60
Write Recovery Time: 6
Read to Precharge Time: 5
READ to WRITE Delay (S/D): 10
Write to Read Delay (S): 4
WRITE to READ Delay (D): 5
READ to READ Delay (S): 6
READ to READ Delay (D): 6
WRITE to WRITE Delay (S): 5
WRITE to WRITE Delay (D): 6
WRITE to PRE Delay: 14
READ to PRE Delay: 6
PRE to PRE Delay: 1
ALL PRE to ACT Delay: 6
ALL PRE to REF Delay: 6
DRAM Static Read Control: Disabled
DRAM Read Training: Auto
MEM. OC Charger: Auto
AI Clock Twister: Lightest
AI Transaction Booster: Manual
Common Performance Level: 9
Pull-In of CHA PH1: DISABLED
Pull-In of CHA PH2: DISABLED
Pull-In of CHA PH3: DISABLED
Pull-In of CHA PH4: DISABLED
Pull-In of CHB PH1: DISABLED
Pull-In of CHB PH2: DISABLED
Pull-In of CHB PH3: DISABLED
Pull-In of CHB PH4: DISABLE
If someone here can give me a hand with that