Mindboggeling OC problem

[Butters_76]

If I set my FSB to anything but 333/1333 the system can't complete post. The computer starts, gfx card info is displayed, post screen flashes and system restarts with M.I.T disabled (back to default speed.

System
Gigabyte X48T-DQ6 (1600FSB certfied 1900Mhz ddr3 certified )
Intel core2duo E-8400
4GB (2x2GB) Corsair DDR3 1600 (PC-12800) modelnumber: TWIN3X4096-1600C7DHX
GF 8800 GT 512MB alpha dog edition
6x SataII HDDs
IDE DVD burner
USB DVD burner (own PSU)
2x USB HDD's (own PSU)
some usb game controllers
Corsair 750W PSU modelnumber: CMPSU-750TXEU

If I set the system FSB to 334 instead of 333 it reboots at start of post. I can even underclock the cpu and memory and it reboots at start of post if FSB is anything but 333.

I have tried F4 and F5 bios (have not tried F6 beta). The wierd thing is that a few months ago before I updated to F5 bios I could start it at 400/1600 and run it for a little while before it restarted, after I updated to F5 it restarts at post if anything but 333 FSB. I have rolled back to F4 but now it restarts at post even with F4 bios.

The system is super cooled. I have a 25cm / 10" fan in front, another at the side and a highspeed 12cm in the back. Zalman 9700 cpu fan. CPU temp 24oC , system 31oC at 333/1333 default cpu speed.

PSU is corsair 750W and it should be plenty to run my system. It's like the CPU is locked at 333mhz, but that can't be it coz it started at 400/1600 before.

It makes no sense. The motherboard is supposed to be a overclockers dream and I can't even overclock 1mhz 333 --> 334.

Any Ideas?

 

[festerovic]

Assuming that you have the board set up perfectly everywhere else (RAM, bus locks, etc)...This may sound wacky, but have you tried going over 400mhz bus? Like 450+? I've heard of "holes" due to bus speed, and going past the "hole" gets thing working again.

Good luck, that kind of thing would really make me angry with my rig.

 

[Butters_76]

I have not tried that, but I'm pretty sure it will not work. I have tried. 266,280.300,334,340,350,366,400 same result on all. It will only finish post if FSB is 333. I have never seen anything like this before and I've overclocked since Celeron 300A like 10 years ago.

 

[leo2kp]

I had a problem like that before where my RAM would not sit nicely in between two numbers, but would always work when overclocked. Very strange.

 

[RJR]

What multiplier?

What voltages??

Do you have all those int. and ext. HDD's, controllers, etc. attached???

Startup in Safe Mode??

Test in Clean Boot Mode???

OS disk Startup Repair??

 

[Butters_76]

Multiplier 9x original, but can do 7x,8x,9x

Correct voltages. All Hdd's attached

Can not startup at all if FSB is not 333. It restarts at post after listing CPU, before counting Memory

Can't get past post, it restarts before it's about to boot

See above. At 333/1333Mhz FSB it works just fine, at anything else, lower or higher it can't finish post (Power On Self Test)

 

[RJR]

OOOPS, Sorry, I should read a little more carefully.

 

[V3NOM]

have you disabled spread spectrum? C1E EIST etc?

 

[Butters_76]

Have now tried them both on and off, same result well except I got passed post at 334 once now, I ctrl+alt+del at select os screen (I dual boot XP32/Vista64) and at next post it restarted again.

This is iso wierd!

 

[V3NOM]

maybe its just a defective motherboard...

 

[Butters_76]

Should it be rock stable at 333 then if the board is defective?

 

[RJR]

Butters if you happen to check back and are still having this problem. I came across a poster on another forum w/Gig mobo with very sim problems as yours.

He solved it by stripping down his system. Just boot drive/ NO USB drives and removed all other non essential parts.

He was then able to overclock and have it post/boot/load without a problem. He then reattached all of his drives etc. he took off and it worked for him.

Just FYI if you check back.