Mobile Pentium 4 in a PC Mobo ?

[archy121]

Does anyone know if i can put a mobile Pentium4 3.2G @533Hz HT (SL77R) in the Abit BE7-Raid motherboard (or any socket 478 northwood supporting motherboard) ??

The motherboards E7 bios can do up to 3.2G @533, HT and is also socket 478.

The CPU & Mobo all match up ok apart from possible voltage difference issues..

Anyone ever tried this ??
Can it be done ?
If it can be done are there any obvious disadvantages to doing this ?

 

[stevty2889]

Yeah, it should work perfeclty fine, the mobile pentium 4's are pin compatable with the desktop parts. I have a 1.6ghz mobile northwood in a desktop 845chipset board. The only issue you may run in to is the chip defaulting to a lower multiplier. It will likely be a good overclocker as well, since the mobile chips are just desktop chips that will run with lower voltage and also run cooler. Have fun, I bet you can get at least 3.6ghz out of that chip..

 

[Zap]

I have a mobile socket 478 Celeron in an Albatron 845PE chipset board. CPU is 1.6GHz and I have it overclocked to around 3GHz. The mobile P4 chips are similar, with one difference. If the chip you have (or are looking at getting) supports SpeedStep, then it has two different multipliers. The "default" 24x multiplier is enabled only if a SpeedStep capable BIOS tells the CPU to run at that speed, otherwise the CPU drops down to (usually) 12X multiplier.

The mobile Celeron doesn't support SpeedStep so it avoids the problem. The Celeron also runs at 400MHz FSB so it is easy to OC on a board that supports 533MHz FSB.

 

[TStep]

It will probably work, but as stated above, it's going to befault to a 12x multiplier. So just to get the cpu running at it's rated speed of 3200, your going to need a front side bus of 267 (12x267). fsb=267 is a speed that your BE7 will probably not be able to attain, let alone the DDR. I think you will more than likely require a premium 865/875 based board to reap the perfromance levels the cpu is capable of. In addition 865/875 brings the additional performance of DC ram and the downward memory ratios.

 

[Spikesoldier]

sell it and get a 2.4C same 12x multiplier

 

[archy121]

Thanks for all you feedback !

I actually have a 2.5G p4 in the system running fine but looking little old for some of the video editing work i do at times.

I really love this motherboard and it has worked really well for me to date. Also i have invested in 4x 200M 7200rpm 8M cache IDE drives that are setup in raid & work extremely fast. I am reluctant to upgrade to a new motherboard as it will probably not support IDE raid & also there are too many changes happening in the industry at the moment. Rather wait a year for dust to settle.

I am aware that the fastest processor i can i can officialy support is the 3.06G P4 @ 533FB with HT. A 3.2G version of it would have also worked but Intel didnt do one. The 3.06G is no longer available other than on ebay & they go for silly prices.
So i thought i might do one better & get the Mobile Pentium 4 at 3.2G @533 with HT to work at a lower price & possibly higher performance.

My motherboard allows me to manually select CPU type to 3.2G CPU (max value)
- CPU external clock frequency can be set to max 250
- Multiplier i think goes to 24x max

-Does knowing the above information help answer if a 3.2 Mobile pentium will work ?
-Will there be a Voltage problem.. ie motherboard supplying too high a voltage by deault ?


Further ideas & experiences would be appreacited

 

[archy121]

ZAP -

"The "default" 24x multiplier is enabled only if a SpeedStep capable BIOS tells the CPU to run at that speed, otherwise the CPU drops down to (usually) 12X multiplier. "

But if my motherboard allows me to manually set multipler to 24x... Will the chips setting overide this & still run at 12X ???

 

[rogue1979]

You will get a 12X multiplier, no way around that with a P4-M. Most motherboards support the P4-M, but there are some that just can't deal with the default 1.30v and will not boot.

The SiS661FX sets the default voltage to 1.60v on any P4-M.

 

[Zap]

AFAIK 12x mult only.

There is a voltage mod that can be done to increase motherboard compatibility. Don't quote me on this, but I think the trick is to disconnect (bend away or break off) the VID pin closest to the edge of the CPU.

 

[themroc]

Originally posted by: stevty2889
Yeah, it should work perfeclty fine, the mobile pentium 4's are pin compatable with the desktop parts. I have a 1.6ghz mobile northwood in a desktop 845chipset board. The only issue you may run in to is the chip defaulting to a lower multiplier. It will likely be a good overclocker as well, since the mobile chips are just desktop chips that will run with lower voltage and also run cooler. Have fun, I bet you can get at least 3.6ghz out of that chip..

Out of interest, what motherboard are you running your p4M on? What speed of memory are you using? I assume the board allows you to run your memory at a reduced fraction of the FSB speed?