P7P55D PRO i5-750 Help needed

I'm a beginner with overclocking. I just built a system, and I tried using the i3/i5/i7 OC guide in the how-to section of this web site. Unfortunately, there are a few differences between my BIOS and the settings the guide uses. For example, there is no VTT voltage, IOH voltage, or DRAM multiplier (that I know of) listed in my BIOS settings. I tried a few other methods of overclocking I found around the web, and I eventually got a memory dump during startup. When I reset the BIOS to the original settings, Windows is now loading very slowly, and the RAID is not initializing.

Please help me with these two things:
1. What is going on with the RAID?
2. How should I properly overclock this system?

System Specs:
Mobo: ASUS P7P55D PRO LGA 1156 Intel P55 ATX Intel
CPU: Intel Core i5-750 Lynnfield 2.66GHz LGA 1156 95W Quad-Core
RAM: CORSAIR XMS3 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (9-9-9-24)
VGA: EVGA 896-P3-1255-AR GeForce GTX 260 Core 216 896MB 448-bit GDDR3
HDs: Western Digital Caviar Black 500GB 7200 RPM SATA (x2 RAID1)
Cooling: XIGMATEK HDT-S1283 with Arctic Silver 5

I installed Windows 7 Ultimate, flashed the BIOS, and have all the latest drivers installed. Everything was working perfectly before I attempted overclocking... maybe I shouldn't fix what's not broken.

The RAID rebuilt itself after several hours. It is now showing a normal status. Now there is the little issue of overclocking my system. Does anyone here have experience with the ASUS P7P55d PRO with i5-750?

I'm out of the country and will help you when I'm back on Wed, got your PM

Thank you! I look forward to it.

I have the same board...

My bios has the following

CPU Voltage
IMC Voltage
Dram Voltage
CPU PLL Voltage
PCH Voltage

IMC = VTT
Vcore is my CPU Voltage
vDIMM is my DRAM voltage

Bump. I still haven't heard from Brollocks.

OK, set v-core at 1.35v, Vtt (IMC voltage) at 1.3 v
Disable C1E, speedstep and C-State
Set DRAM voltage at 1.65v, leave all other voltages on auto
set multi at 20 and bclck at 200, that will give you 4 ghz straight

Start here and we will take it up a notch

Thanks for getting back to me. I put in the settings you specified. The computer booted. I ran Prime95 Torture tests, both Blend and Large FFTs. Two of four cores failed almost instantly on both tests. Here are my current BIOS settings:

Ai Tweaker
Ai Overclock Tuner [D.O.C.P.]
DRAM O.C. Profile [DDR3-1600MHz]
CPU Ration Setting [20.0]
Intel(R) SpeedStep(TM) Tech [Disabled]
Xtreme Phase Full Power Mode [Enabled]
BCLK Frequency [200]
DRAM Frequency [DDR3-1600MHz]
QPI Frequency [Auto]
ASUS/3rd Party UI Priority [ASUS Utility]

DRAM Timing Control
CAS# Latency [9]
RAS# to CAS# Delay [9]
RAS# PRE Time [9]
RAS# to RAS# Delay [24]
ALL OTHER SETTINGS [Auto]

CPU Differential Amplitude [Auto]
CPU Clock Skew [Auto]

CPU Voltage Mode [Manual]
Fixed Voltage [1.35000]
IMC Voltage [1.30000]
DRAM Voltage [1.6500]
CPU PLL Voltage [Auto] (currently showing 1.825V)
PCH Voltage [Auto] (currently showing 1.059V~1.062V)
DRAM DATA REF Voltage on CHA [Auto]
DRAM DATA REF Voltage on CHB [Auto]

Load-Line Calibration [Auto]
CPU Spread Spectrum [Auto]
PCIE Spread Spectrum [Auto]

Advanced - CPU Configuration
CPU Ratio Setting [20.0]
C1E Support [Disabled]
Hardware Prefetcher [Enabled]
Adjacent Cache Line Prefetch [Enabled]
Max CPUID Value Limit [Disabled]
Intel(R) Virtualization Tech [Enabled]
CPU TM Function [Enabled]
Execute-Disable Bit Capability [Enabled]
Active Processor Cores [All]
A20M [Disabled]
Intel(R) SpeedStep(TM) Tech [Disabled]
Intel(R) C-State Tech [Disabled]

Increase IMC voltage to 1.325v

Sounds good. I will do that when I get home from work. Until then, are there other things in the BIOS you like to enable/disable? Is the RAM set up correctly?

I put in 1.325 for IMC Voltage, and the computer didn't seem to like it. Windows booted, I ran Prime95, it looked like only three cores were working, and one failed instantly.

Mmmm, up IMC to 1.35v

I upped the IMC to 1.35. Again, one of the cores failed instantly. I'm starting to get concerned. My understanding of this setup is that I should have no problem getting 4.2 out of this board/CPU. Could it be how the RAM is configured in the BIOS?

That is real odd, you should be 4 Ghz stable at those settings, increase v-core to 1.33v, if it is stable then back down Vtt a tad

I just want to verify those numbers. You said increase v-core to 1.33V. I have been using 1.35V for this voltage, so this would actually be a decrease. Have I been running v-core too high this whole time? Also, can you verify that what this BIOS calls Fixed Voltage is the v-core?

update: I tried
Fixed voltage 1.33
IMC voltage 1.325

I got a memory dump on startup.

I tried TurboV today... the results were pretty ugly. I will try the auto overclocker soon if I can't get this figured out otherwise.