Thinkpads Forum

First, I have read through all the posts in the 600 upgrade area, but I still am not clear/ready to buy an upgrade because of questions.

I recently acquired a base model 600 (2645-51U), it currenlty has a PII-266 and if the price is right, I would like to take it to the fastest processor it will support. I've read differing stories on the PII-400 MMC-1 module, with one poster claiming it worked great for him, and another saying they never could get it to work OK on theirs.

Is the factory max PII-300 the best I can do? I doubt I would gain much over the 266 in that case, probably not worth the effort to change.

Open to all feedback and opinions, thanks in advance.

Thomas DeSmit

I found this topic doing a search and it asks my question exactly. I have the exact same model tp. What are my options for cpu(how high can I go?)

If you have a ThinkPad 600, you can use any CPU contained on an MMC-1 module. If I'm not mistaken, the fastest CPU to use the MMC-1 format is the 400mhz Pentium II. I'm not sure how well it'd work out since I don't have an original ThinkPad 600 but I don't see why an upgrade wouldn't work. However, I'm sure the 400mhz MMC-1 modules are not exactly "Easy" to find.

AlphaKilo470 is correct. The fast processor that you can buy is a 400MHz MMC-1. They are pretty hard to find, not to mention expensive.

It should also be said that you CANNOT use the Celeron chips that are out there, though I haven't tried this myself. The Celeron chips are about half the price of the regular ones.

I believe that the ram is also capped at 288MB, though again, I haven't tested it.

400mhz is the max...If you hurry there's an MMC-1 400mhz on Ebay for $49($55 shipped) which is a very good price for that CPU..Type in MMC1 and do a search...

BTW before I sold my 600(which I upgraded to 366mhz) I had 320+ RAM running very stable in it.. I found a 256 RAM on Ebay awhile ago listed as 66/100 LOW DENSITY...I bought it for around $50,I think, and it worked fine...I trying to remember now but I think I had the 256 stick+ a 64+ the 32 thats built in..The BIOS and Windows saw 327 RAM so it must have only been reading 1/2 of the 64 stick...

I had XP on it and it was no speed demon..But for surfing the net it was fine...The problem with the 600 series is you're only going to get so much out of the video card...

BillD wrote:BTW before I sold my 600(which I upgraded to 366mhz) I had 320+ RAM running very stable in it.. I found a 256 RAM on Ebay awhile ago listed as 66/100 LOW DENSITY...I bought it for around $50,I think, and it worked fine...I trying to remember now but I think I had the 256 stick+ a 64+ the 32 thats built in..The BIOS and Windows saw 327 RAM so it must have only been reading 1/2 of the 64 stick...

That's funny, I thought the base 600 could only support up to 288MB (256 in the slots plus the onboard 32)? This could be the beginning of an interesting study...

I know that the 600E and 600X are unable to se Celerons because the Celeron chips don't support the AGP bus which the 600E and X's video uses but the 600 uses PCI bus for everything so I had assumed that a Celeron would work. However, if other people have tried the Celeron in their original 600s, maybe I'm wrong on that.

When I was looking around for a MMC1 to upgrade my 600 at the time there was NO 400 mhz MMC1 Pentium's on Ebay..Only the 366mhz and a 400mhz celeron... I wrote the guy selling the Celeron and he wrote back saying he was pretty sure the Celeron would NOT work in the 600.. So I ended up getting the 366 Pentium...No problems with it, it worked fine....

That's funny, I thought the base 600 could only support up to 288MB (256 in the slots plus the onboard 32)? This could be the beginning of an interesting study...

Yep,I had 320+ in the 600...Like I said I found a 256mb RAM advertised as 66/100 CAS 2 or CAS 3...I bought it and it worked...Maybe I was just lucky..Since I've been poking around these 600 series machines all the different Motherboards and quirks is enough to make your hair hurt...

Isn't the 288MB RAM cap overcome with the BIOS upgrade -- or is that just for the 600 E and X models?