Help needed: Asus P4P800-SE & Celeron D 345 - won't boot

[SMcA]

Summary of my computer:

Asus P4P800-SE motherboard BIOS Version 1011
OCZ 2x512MB PC3200 Dual Channel DDR-RAM
ATI Radeon 9550 with 256MB VRAM
LG DVD+/-RW drive
Maxtor 250GB hard disk with 16MB cache

Right now I am using a Pentium M 1.4GHz overclocked to 1.82GHz (using Asus CT-479).

When I swap the processor with a Celeron D 345 3.06GHz, the system won't boot. Resetting the CMOS didn't help.

The processor works in a MachSpeed Matrix P4M800 motherboard. So the processor is good.

The Asus website says that the processor has been supported since BIOS 1007.

Has anybody come across a similar situation? I would appreciate any possible solutions.

 

[slvr_phoenix]

Resetting the CMOS was my first thought, but you said that you did that. My second thought is maybe it's your power supply, since a PM, even overlcocked like that, probably consumes a lot less electricity than that Celeron D.

 

[SMcA]

I used the same 400W power supply with both mobos... didn't work... I even pulled out all non-essential drives and cards, and swapped the Radeon 9550 with a Rage 128.

 

[slvr_phoenix]

Hmm. Trickier and trickier. Maybe if you manually increase the RAM latencies? Maybe the RAM's SPD settings aren't actually stable at 400MHz. That or up the RAM's VDIMM by .2V or so.

I don't know. I'm running out of ideas.

 

[SMcA]

I am using PC3200 DDR400 RAM. That's 200MHz dual-pumped (400MHz effective / DDR400 ... duh).

If I use the Pentium M 1.4GHz at its native speed, the memory runs at 133MHz dual-pumped (266MHz effective / DDR266). The computer is stable at this setting.

When I overclock the processor by 30%, the memory is running at 133MHz + 30% = 172.9MHz ~ 173MHz dual-pumped (346MHz effective / DDR346).

The system is stable at 5% OC (DDR280), 10% OC (DDR293) and 20% OC (DDR319) as well.

So, the memory is stable at DDR266, DDR280, DDR293, DDR319 and DDR400.

The Celeron D has 533MHz FSB. If I set the FSB😀RAM ratio to 3:4, the memory should run at DDR400, which is what it was made for.

By the way, I used the same sticks of RAM in the MachSpeed motherboard. So I doubt that the RAM is defective/questionable. I doubt if the Asus motherboard supports an FSB😀RAM ratio of 3:5 (Why isn't the memory running at DDR333 when the processor is running at native speed? I can't even change that in the BIOS.)

[ I did a lot of maths above. Give me a nasty reminder / rude awakening if I made any mistakes 😉 ]

 

[slvr_phoenix]

The math is probably right. (I'm too lazy to double check.) But what I'm thinking is that not all motherboards are equal, and between the two chips even, not all FSBs may be equal. I'd try upping the VDIMM slightly if you can, or easing back the memory timings to something a little higher, or both. That's all I can really think of. That or the power supply. If anyone can think of another reason, I'd like to hear it too.