CPU Upgrade questions

I have a Toshiba MX35-S with a Celeron M 340 (1.50gh, 512kb, MHz FSB) on an Intel 855GME chipset. Currently my daughter is using it for school work, IMing, photos & browsing the net, she has two more years till college and a new laptop, until then I want to improve the performance of the Toshiba. I have already maxed the memory, upgraded the HD and now I'm looking to upgrade the processor.

The 855GME chipset allows for both Celeron M and Pentium M processors...

http://compare.intel.com/pcc/showchart.aspx?mmID=3115&familyID=7&culture=en-US

My questions are, outside of the FSB (MHz) and package type (478 pin) what other specs are important? IE... core voltage, L2 cache, manufacturing technology...
Is a 1.8gh, 256mb L2 cache CPU faster than a 1.7gh, 1gb L2 cache or 2.2gh, 256mb L2 cache?

I know it will only be a small performance increase, but these processors can be bought for $15 to $20, dirt cheap, well worth it for +2 more years of use.

 

It depends onw whether you ned the processor upgrade. Have a look under the "Performance" tab in Task Manager, and look if the processor is consistently hitting the 100% mark. If not, then a processor upgrade won't make much different to the overall performance of the notebook.

 

Unlikely to do anything to improve performance but battery life should be affected in a good way. On my old laptop, I usually downclocked my CPU to 600Mhz and it would run most tasks just fine. Performance isn't really something most people need unless they are encoding audio/video.

 

cel M hits 100% almost every other second, maybe I should get something more powerful; wait, I did, Acer just won't fix it!!!

 

What would be best is to get a Pentium M of some sort, and get away from the Celeron M's. That will give you a good performance boost, period.

 

The Celeron-M to Pentium-M upgrade has been done before, but I don't recall it being on this chipset. It should work but my only concern is CPU voltage.

The Banias (130nm) Celeron-M runs at 1.356V. The Banias Pentium-M runs at a maximum 1.388 volts on the lower clock-speed models and 1.484 volts on the more mainstream models. I'd make sure you have either Notebook Hardware Control or RM-clock installed on the laptop and you should become familiar with one of them before you make the change. Also read reports on undervolting Pentium-Ms. If it boots, I would go straight to one of these apps and undervolt the cpu down to closer to where the Celeron was running. Don't worry about wattage as the Max TDP for both chips is 24.5 Watts.

Good luck! I don't see why it shouldn't work, it has done before.

 

In addition to moon angel's post, it may be useful to know the chipset will onyl support a 400 MHz FSB, which means that you can only choose from Pentium M 7X5 processors. Also, if you choose to upgrade, you may need a BIOS update to support the Pentium M. Then BIOS may also put a limit, on which processor you can use up to.

 

Noooooo! Sorry Zero but the Intel 855 chipset only supports Banias Pentium-Ms, these don't have model numbers. The 7** Pentium-Ms are Dothan Core based (yes even the 400MHz FSB ones) and all have 2Mb L2 cache. These are supported by Intel 915 and I think ATi x200m but certainly not Intel 855! For intel 855 you want a Banias P-M which have no model numbers and have the 130nm manufacturing process and 1Mb L2 cache.

As for the BIOS, great point, make sure you have the very latest BIOS for your laptop before making the change. Toshiba's support website should be able to offer the latest one.

 

Sorry, misread there . Yes, what moon angel has said is correct. Only a Banias cored Pentium M will work.

 

Thanks all, I appreciate the info. Moon Angel, that was exactly what I needed to know. Intel shows the 855 chipset supporting both P-M and C-M, but I wasn't sure if I had to stay with the Banias (130nm) or could go with the Dothan (90nm). Thanks for the tip on RM-clock, it looks like that will do the trick for CPU voltage.

 

Update..

I did some more research and found that others have installed 7x5 (Dothan) processors with the 855 chipset with great success. I bought a Pentium M 725, 1.6ghz, 400mhz FSB, upgraded the bios, popped in the processor and hit the power button... It booted up and seems to be running just fine. The voltage is around 1.35v, which according to Intel's specs, is right at the high end for the 725. So far I'm seeing a nice little bust in startup and program launching time. I've seen about a 30% decrease in time running Super Pi, and roughly a 25% increase running PCMark05. Not too bad for a $27 investment. Just what I was looking for to extend the life of this laptop for a few more years.

Thanks for all the help.

 

If it got past the POST, you should be pretty much golden Congrats on your upgrade, glad it's running better for you. It's rare that the processor is what's too slow, but it does happen apparently.

 

Hi, I just googled and found this article. My laptop is gigabyte N501 and it has 855 chipset. I have Pentium M 1.86GHz (750) 90nm Dothan prcessor. It is working fine. When i run cpuid it shows that my processor is running at 1.4 Ghz and FSB at 400MHz (750 has 533FSB). I was looking for an answer since last 1 year and after above discussion i have concluded that my damn bios cannot run this processor at full capacity and stupid gigabyte has no more bios updates. Any suggestions????
My bios version is insyde v1.5

 

Buy a 7x5 Pentium M.

 

The intel 855 chipset only runs 400mhz. Are you 100% sure you've got a 750 not a 745?

 

Ha, classic. The 855 chipset only supports 400Mhz processors, running a 750 would yield 1.4Ghz only from the processor. The Dothan 533Mhz will "work" on the 855 chipset, but it will never run at it's full speed. No BIOS update can physically change the chipset limitations.

The 750 Processor runs at 14 x 133mhz (133mhz Quad pump FSB = 533Mhz). Now the 855 chipset only supports 100mhz FSB processors maximum so when you pop in your P-M 750 it will only run at 14 x 100 = 1400Mhz.

You need a 7X5 processor that runs at 400Mhz(100Mhz) Bus speed. ie; 755
20 x 100Mhz = 2Ghz