I don't remember what I needed to get past 3.2GHz, but I'm at 1.5125v (1.488v actual) now at 3.6GHz.
Have you messed w/ clock over-charging mode? I have mine set to 1.0v.
Here's my BIOS settings from another thread I started a while back. I just updated it again, b/c I made some RAM changes recently. I have bumped up my PLL, FSB, NB, and RAM voltages to counteract a BSOD I got w/ the new RAM settings, but I haven't isolated the culprit yet. My previous settings w/ RAM 1:1 (900MHz) had those settings at 1 notch lower.
Updated BIOS settings/notes:
JumperFree Configuration Settings
AI Overclocking: Manual
CPU Ratio Control: Auto (manual for testing)
- Ratio CMOS Setting: 8
FSB Strap to Northbridge: Auto
FSB Frequency: 450 (Max is 480 for me w/ multi at 7)
PCI-E Frequency: 100 (110 didn't allow any additional OC on GPU)
DRAM Frequency: DDR2-1125
DRAM Command Rate: 2T
DRAM Timing Control: Manual
CAS# Latency: 5
RAS# to CAS# Delay: 5
RAS# Precharge: 4
RAS# Activate to Precharge: 10
TWR: can't remember
TRFC: 30
TWTR: 3 (shows up as 11 in memset [skewed])
TRRD: 2 (shows up as 10 in memset [skewed])
TRTP: can't remember
DRAM Static Read Control: disabled (I can't enable this and TB at the same time)
Transaction Booster: Enabled
Boost/Relax Level: Level 2 (corresponds to Performance Level = 6)
Clock Over-Charging Mode: 1.000v (had on AUTO, but higher FSB speeds demanded 1v. I may be able to turn this back down a bit for 450)
CPU Spread Spectrum: Disabled
PCIE Spread Spectrum: Disabled
CPU Voltage: 1.5125v (anything lower gave me core failures after 1.5-2hrs. 1.6v allowed 3.8GHz, but I think a little more is needed for P95.4 stability)
CPU Voltage Reference: 0.63x (I wasn't getting much over 3.2GHz until I changed this from Auto. 0.57x, and 0.59x wasn't stable. 0.61x worked, but I have a feeling 0.63x is best.)
CPU Voltage Damper: Enabled
CPU PLL Voltage: 1.70 (I may be able to reduce this to 1.6 for 450FSB. At 480FSB 1.5-1.6 [or 1.7?] wasn't stable, [1.7?], 1.8-2.2 worked.)
DRAM Voltage: 2.2 (2.3 was used to ensure stability through testing, but 2.2 should be fine, maybe 2.15)
FSB Termination Voltage: 1.40 (1.5 for 480FSB, I may be able to go lower at 450)
North Bridge Voltage: 1.55 (1.8 for 480, anything higher is actually worse)
North Bridge Voltage Reference: AUTO (0.67x for 480FSB, auto seems to work best for 450)
South Bridge Voltage: 1.05 (I had it at 1.2 during testing to ensure stability...don't know if it helped)
Advance CPU Settings
CPU Ratio Control: Auto (manual for testing)
- Ratio CMOS Setting: 8
C1E Suppport: Enabled (disabled for testing)
Max CPUID Value Limit: Disabled (I just left this disabled, I don't know if it hurts or helps)
Vanderpool Technology: Disabled (I just left this disabled, I don't know if it hurts or helps)
CPU TM Function: Enabled
Execute Disable Bit: Enabled (Not sure what this does, but I've seen others w/ it enabled)
PECI: Enabled
Hope this helps!