GA-EP45-UD3P New CPU Heatsink Problem

[JarthMader]

Motherboard: GA-EP45-UD3P Rev 1.6
CPU: Core 2 Duo E7500 (stock 266x11 = 2.93GHz)
RAM: 8GB (4x2GB) OCZ Gold DDR2 800 (5-5-5-18)

I was using the stock HSF for the E7500 but I was concerned about the pop-in mounting system so I opted for a nice big Zalman heatsink (CNPS9500AT).
Before I installed this I was running a very slight and stable overclock of just 273x11 (to get up to 3.0GHz). After installing the Zalman HSF, my system won't boot if the CPU Host Clock Control setting is enabled. Even if I don't change the CPU Host Frequency from it's default of 266, it will still fail to boot. Other settings in the M.I.T. menu don't cause this problem (I can change the multipliers, voltages, RAM timings, etc, and it will still boot fine). This is incredibly baffling to me because the only electrical difference would the the Zalman fan vs the Intel fan, but the CPU fan control setting is under the PC Health Status menu, changes to which also don't cause boot problems.
It's Prime95 stable with the default settings but I would really like to try some serious overclocking now that it runs so much cooler (load temp is 48C, whereas it was 64C with the stock HSF).
Any help would be greatly appreciated.

[rbmorse]

I dunno. In my opinion, you went from the second worst HSF retaining method ever devised (Intel push pin) to the worst (Zalman cross bar). I really hate that part on mine .

I didn't have the problem you experienced when I put the CPNS 9500 on my E8400 in my EP45-UD3P, but for the sake of experimentation try taking a 1/4 turn out of the screw on one side of the retainer clip (reduce the clamp pressure just a bit). It won't hurt anything and may help if the problem is a physical misalignment (although I don't see how that could happen on Socket 775, but what do I know)?

The next thing (and it's another long shot) would be to pull the mobo (again) and carefully examine the bottom where the Zalman-supplied support bracket comes into contact with the motherboard. Maybe one of the component tails that Gigabyte so helpfully fails to trim back became bent and is shorting.

[JarthMader]

Well, I just completely reassembled my computer, being sure not to impact any of the leads on the back of the board with the HSF backplate (none were bent) and not to over tighten the HSF clip. It still has the boot problem.

BIOS Settings
MB Intelligent Tweaker(M.I.T.)
Robust Graphics Booster ..................: Auto
CPU Clock Ratio ..........................: 11x
Fine CPU Clock Ratio......................: +0.0
CPU Frequency ............................: 2.93 GHz (266x11)

Clock Chip Control
Standard Clock Control
CPU Host Clock Control....................: [Disabled]
CPU Host Frequency (Mhz) .................: 266
PCI Express Frequency (Mhz) ..............: 100
C.I.A.2 ..................................: [Disabled]
 
Advanced Clock Control [Press Enter]
CPU Clock Drive...........................: 800mV
PCI Express Clock Drive...................: 900mV
CPU Clock Skew (ps).......................: 0
MCH Clock Skew (ps).......................: 0

DRAM Performance Control
Performance Enhance.......................: [Standard]
(G)MCH Frequency Latch....................: [266MHz]
System Memory Multiplier .................: 3.00A
Memory Frequency (Mhz) ...................: 800
DRAM Timing Selectable ...................: [Manual]

Standard Timing Control
CAS Latency Time..........................: 5
tRCD .....................................: 5
tRP'......................................: 5
tRAS......................................: 18

Advanced Timing Control
tRRD......................................: 5
tWTR......................................: 5
tWR.......................................: 8
tRFC......................................: 56
tRTP......................................: 5
Command Rate (CMD) .......................: 2

Driving Strength Profiles (A and B)
Driving Strength .........................: 800 MHz
Everything Else ..........................: Auto

Channel A
Static tRead Value........................: 12
tRD Phase0 Adjustment.....................: Auto
tRD Phase1 Adjustment.....................: Auto
tRD Phase2 Adjustment ....................: Auto
tRD Phase3 Adjustment.....................: Auto
Trd2rd(Different Rank)....................: Auto
Twr2wr(Different Rank)....................: Auto
Twr2rd(Different Rank)....................: Auto
Trd2wr(Same/Diff Rank)....................: Auto
Dimm1 Clock Skew Control..................: Auto ps
Dimm2 Clock Skew Control..................: Auto ps
DDR Write Teaining........................: Auto

Channel B
Static tRead Value........................: 12
tRD Phase0 Adjustment.....................: Auto
tRD Phase1 Adjustment.....................: Auto
tRD Phase2 Adjustment ....................: Auto
tRD Phase3 Adjustment.....................: Auto
Trd2rd(Different Rank)....................: Auto
Twr2wr(Different Rank)....................: Auto
Twr2rd(Different Rank)....................: Auto
Trd2wr(Same/Diff Rank)....................: Auto
Dimm1 Clock Skew Control..................: Auto ps
Dimm2 Clock Skew Control..................: Auto ps
DDR Write Training........................: Auto

Motherboard Voltage Control
CPU
Load Line Calibration.....................: [Enabled]
CPU Vcore....................1.26250V.....: 1.30000V
CPU Termination..............1.200V.......: 1.200V
CPU PLL......................1.500V.......: 1.500V
CPU Reference................0.760V.......: Auto

MCH/ICH
MCH Core.....................1.100V.......: 1.260V
MCH Reference................0.760V.......: Auto
MCH/DRAM Ref.................0.900V.......: Auto
ICH I/O......................1.500V.......: Auto
ICH Core.....................1.100V.......: Auto

DRAM
DRAM Voltage.................1.800V.......: 2.000V
DRAM Termination.............0.900V.......: Auto
Channel A Reference..........0.900V.......: Auto
Channel B Reference..........0.900V.......: Auto

Advanced Settings
Limit CPUID Max. to 3.....................: [Disabled]
No-Execute Memory Protect.................: [Enabled]
CPU Enhanced Halt (C1E)...................: [Disabled]
C2/C2E State Support......................: [Disabled]
x C4/C4E State Support....................: [Disabled]
CPU Thermal Monitor 2(TM2) ...............: [Enabled]
CPU EIST Function.........................: [Disabled]
Virtualization Technology.................: [Disabled]

With those settings this is what I get in the PC Health Status menu:
Attachment 2041

Another problem has now popped up. The Vcore apparently responds to changes in MIT (although CPU-Z reports 1.248V), and the DDR stays the same no matter what the setting. Is this a known issue that could be fixed by a BIOS update (my current BIOS is FB, dated 5/20/2009)?

[JarthMader]

Some good news. I went ahead and pulled the trigger on the BIOS update and it worked, for the most part. However, right after I updated the BIOS, the PC Health Status menu had DDR18V at 1.936V, but after loading up the default settings and rebooting, it continues to read 1.824V even when it's set to 2.0V in M.I.T. Is there some other setting that affects this?

Edit: Apparently it just needed a bit of overclocking to get it in the mood. I bumped up to 333x11, set MCH latch to 333 and the multiplier to 2.40B, and it's reading 2.02V (set to 2.0V in BIOS). I obviously don't know if it's stable yet but that's what I'll be working on next.