Great Forum. Lots of knowledgeable people around. This is my first post here and I have a problem where I hope to get some input from you.
Let me describe my problem:
I have my system overclocked to an amount that is absolutely rock-stable with any stressing software I fire at it. But in Games, it fails. CTDs, even bluescreens or freezes. I've tested Assassin's Creed and Grand Theft Auto IV so far, they're both highly unstable when overclocked to a certain amount, and rock-solid when @ default settings.
So, the "unstableness" only occurs when playing games. The question is: Why?
Board: GigaByte GA-P35-DS3 Rev 2.0 F14 bios
CPU: C2D E8400 (E0)
Cooler: Arctic Freezer 7 Pro
RAM: Transcend aXeRam DDR2 1066+ 2GB Kit *Overclocking Memory Modules*
GPU: Zotac GeForce 8800 GT (std Zotac clocks)
PSU: Seasonic S12II 430W
HDD: WD3200AAKS (Caviar Blue)
OS: Clean install of Windows XP SP3
This is my setup. Stressed with the following so far:
Robust Graphics Booster___________ [Auto]
CPU Clock Ratio___________________ 
Fine Clock Ratio__________________ +0.0
CPU Frequency _________________ 3.99GHz (444x9)
CPU Host Clock Control____________ [Enabled]
CPU Host Frequency (MHz)__________ 
PCI Express Frequency (Mhz)_______ 
C.I.A. 2__________________________ [Disabled]
Performance Enhance_______________ [Standard]
System Memory Multiplier_(SPD)____ [2.40]
Memory Frequency(Mhz)_____800_____ 1066
DRAM Timing Selectable___(SPD)____ [Manual]
CAS Latency Time________________ 
Dram RAS# to CAS# Delay_________ 
Dram RAS# Precharge Delay_______ 
Precharge Delay (tRAS)__________ 
ACT to ACT Delay (tRRD)__________ [Auto]
Rank Write to READ Delay_________ [Auto]
Write to Precharge Delay_________ [Auto]
Refresh to ACT Delay_____________ [Auto]
Read to Precharge Delay__________ [Auto]
Static tRead Value_______________ [Auto]
Static tRead Phase Adjust________ [Auto]
System Voltage Control_______ [Manual]
DDR2 OverVoltage Control_____ [+0.3V]
PCI-E OverVoltage Control____ [Normal]
FSB OverVoltage Control______ [Normal]
(G)MCH OverVoltage Control___ [Normal]
CPU Voltage Control__________ [1.23750] (CPU-Z: 1,200v Idle / 1,168v Load -> Vdroop ~0,03v)
Limit CPUID Max. to 3.....................: [Disabled]
No-Execute Memory Protect.................: [Enabled]
CPU Enhanced Halt (C1E)...................: [Disabled]
CPU Thermal Monitor 2(TM2) ...............: [Disabled]
CPU EIST Function.........................: [Disabled]
Virtualization Technology.................: [Disabled]
Legacy USB Storage Detect__________________ [Disabled]
The type of crashes, especially the occurence of nv4_disp.dll might lead one to think of faulty drivers/GPU. This is NOT the case as seen below. No artifacts anywhere.
OC 4GHz (above settings)
Prime95 Small FFTs_________________________ 17h no errors
Prime95 Blend______________________________ 14h no errors
Prime95 Blend + FurMark simultaneously_____ 13h no errors
OCCT (CPU: OCCT) Auto (1h) | Medium Data Set | priority NORMAL___________ no errors
OCCT (CPU: OCCT) Auto (1h) | Medium Data Set | priority HIGH_____________ no errors
OCCT (CPU: Linpack) Auto (1h) | Max______________________________________ no errors
OCCT (Power Supply) Auto (1h) | Shader complexity 0______________________ no errors
OCCT (Power Supply) Auto (1h) | Shader complexity 8______________________ no errors
MemTest86+ BootCD all tests___________ 8h no errors
MemTest86+ BootCD Test #5_____________ 20 passes no errors
3DMark06 default settings_____________ no errors
3DMark06 1680x1050 highest settings___ no errors
Grand Theft Auto IV__________ Random crashes within minutes: mostly CTD. rarely BSOD nv4_disp.dll.
Assassin's Creed_____________ Random crashes: mosaic-type freeze, blue-violettish colors.
Grand Theft Auto IV__________ no errors
Assassin's Creed_____________ no errors
What I've tested so far to get the games stable:
Furthermore I can exclude the following:
Different GPU & drivers_________________________ no improvement
Increased CPU Voltage Control___________________ no improvement
Increased FSB OverVoltage Control_______________ no improvement
Increased (G)MCH OverVoltage Control____________ no improvement
Increased FSB & (G)MCH OverVoltage Control______ no improvement
Increased DDR2 OverVoltage Control______________ no improvement
Loosened RAM Timings____________________________ no improvement
Different RAM Modules___________________________ no improvement
Clocked down to 3.6 GHz_________________________ seems stable (2h-3h hours GTAIV without crash)
*GPU drivers were correctly installed/uninstalled with DriverSpeeper/DriverCleanerPro.
- Too high temperatures: Ingame never gets over 55-60°C CPU | 80-85°C GPU | 50°C MB
- FSB too high: If I lower the clock ratio and leave FSB @ 444, it's stable.
I don't understand why games won't do properly but Prime/OCCT/FurMark/3DMark06 pass without problems. As stated, if I clock down to 3.6 GHz GTAIV seems stable. I don't understand it why it's not at 4GHz. It seems that Games don't like my processor running too high even if it passes those stressing-software, for whatever reason. It's fine at 444 FSB with lower multi, but hangs at higher multi when the CPU clock is too high. That annoys me as I don't understand it.
Maybe a different Motherboard would help? But I see no point why that would do.
Maybe someone has an idea what else could be the problem here?
Any advice would be great. I'd really appreciate it. Been trying for the past days (weeks!) without success. I'm at a loss.
Thanks for reading.
Hope I did everything right with my first post