Pentium 4 3ghz Mobile on Desktop Mainboard

[ozzielee]

Hello everyone,

I need help. I have a PIV mobile 3.06ghz CPU and installed in on my ABit IC-7G mobo. The mainboard POSTS everytime but only at 1600mhz (133FSBx12). No matter what I try the multiplier seem to be locked at 12X. Hence in order for it to run at its rated speed of 3ghz, I would have to increase the FSB to 250. However any FSB inexcess of 200mhz and it does not POST.

Is there a mod or way of changing the multiplier ? Else I will be stuck at with a PIV 3ghz running only at 2400mhz. I am using DDR 400 (PC3200).

All u computer gurus, pls help me.

Thanks.

 

[rogue1979]

All P4-M cpu's default to a 12X multiplier on a desktop motherboard.

Only using a motherboard that supports a high fsb will give you 3GHz. No way to change the multiplier. But you can use a memory divider if you have the option in your bios to lower the memory frequency to run PC3200 speeds at a higher than 200MHz fsb.

Welcome to Anandtech Forums.

 

[ozzielee]

Hi rogue,

Thanks for reply. After more tweaks I can only get it to post at 2.4ghz (200x12). Voltage is set to 1.3V.

Maybe I need to get faster RAM or increase voltage to get it POST.

Has any1 successfully ran the PIV mobile 3.06ghz at the rated speed? If yes, pls advise.

Thanks
Ozzie

 

[rogue1979]

Hey ozzie, did you try to set the memory divider lower if one was available in the bios?

For instance, one of my rigs is running a P4-M 1.6GHz at 12 x 200 for 2.4GHz. But my fsb options would allow me to run a 250MHz fsb to speed up the cpu and use a lower memory divider to still run the ram at 400MHz.

Of course, the cpu won't run that fast, but I could run a higher rated P4-M faster that way.
Socket 478 gives you no performance penalty for running asynch memory speeds, unlike socket A.

I also have a mobile Celeron 1.8GHz (256k) running on a 165MHz fsb (2988MHz). Again, using the memory dividers I am able to speed up my memory to run 400MHz DDR for better performance. It works both ways if you have the divider settings in the bios.

What brand/model/chipset motherboard are you working with?

 

[ozzielee]

Hi rogue,

I using an ABit IC-7G mobo with 875chipset. Under the memory timings there are only 3 options: 1:1, 4:5, or by SPD.

However there is a NB strap feature that gives several options : FSB400, FSB533, FSB667 and FSB800. I not use what this does and hence have not tweaked it much. (i've left it at default setting).

I see there is a nice article/guide on Celeron mobile overclocking but none for a PIV mobile.
Do u know if there are any desktop mobos that have Speedstep enabled in the BIOS ? I was told that would fix the problem and allow the CPU to run at its rated speed of 3.06ghz.

Cheers

 

[rogue1979]

I did a quick google and tried to find info on speedstep enabled for a desktop motherboard.

Several forums discussed a bios feature/issue to allow the stock multiplier to be enabled, but nobody came up with anything.

An 875 is a nice motherboard, so maybe at this point you could sell the 3.06GHz on ebay and get a different cpu? If you have fsb options by 1MHz increments you could pick a slower P4 and overclock like a 2.26b or 2.4b? The mobile celeron is also popular and very cheap.

Sorry I couldn't find anything to help so far....

 

[ozzielee]

Hi Rogue,

Finally got it up and running at 3.18ghz. I set the FSB to 265. Before it wouldnt POST. But since I changed the NB strap to FSB800, it posts and it runs fine and very stably. Also when I changed the NB to FSB800, the 5:4 CPU/RAM ratio suddenly appeared and that's what it is currently set at.

Its's not much of an overclock as the CPU's rated speed is 3.06ghz. I wonder how much further I could overclock the FSB - what the limit on the 875chipset. (in the BIOS i could set it to 400mhz FSB but there is prob no RAM that can handle that speed)

Cheers

 

[rogue1979]

glad to see you got it running! I don't know what the limit on the fsb is, but as long as you use the memory divider to keep the DDR speeds reasonable, there is no reason not to try faster.

 

[themroc]

Originally posted by: rogue1979
Hey ozzie, did you try to set the memory divider lower if one was available in the bios?

For instance, one of my rigs is running a P4-M 1.6GHz at 12 x 200 for 2.4GHz. But my fsb options would allow me to run a 250MHz fsb to speed up the cpu and use a lower memory divider to still run the ram at 400MHz.

Of course, the cpu won't run that fast, but I could run a higher rated P4-M faster that way.
Socket 478 gives you no performance penalty for running asynch memory speeds, unlike socket A.

I also have a mobile Celeron 1.8GHz (256k) running on a 165MHz fsb (2988MHz). Again, using the memory dividers I am able to speed up my memory to run 400MHz DDR for better performance. It works both ways if you have the divider settings in the bios.

What brand/model/chipset motherboard are you working with?

What motherboard are you using for your P4M?

 

[rogue1979]

Asus P4S800-MX