[ltp] Re: adding RAM to a T20

[Alex Deucher]

On 2/16/07, Wookey <wookey@aleph1.co.uk> wrote:
> On 2007-02-16 18:47 +0000, Simon Williams wrote:
>
> (apologies for thread-hijack by T21 owner)
>
> > John Shane wrote:
> > >If a stick of 128MB PC100 RAM pulled from a T23 will work in your
> > >T20 then I have one that you can have for the cost of postage. Contact
> > >me off list if you want it and we can work out the details.  John
> >
> > No it won't. I tried exactly the same thing when my new T23 kept
> > freezing (video card it turned out- IBM replaced mobo).
> >
> > The T20 (and probably T21 and T22) use PC100. The T23 uses PC133. PC100
> > will not work in a T23, and PC133 will not work in a T20.
>
> I've seen this written on the thinkwiki too, but I was under the
> impression that faster modules would normally work on slower machines
> (just at the slower speed). Is there something special about the T21
> controller that makes it refuse to talk to PC133 RAM?
>
> Also I note that crucial com recommend this:
> http://www.crucial.com/store/mpartspecs.aspx?mtbpoid=6A35075BA5CA7304
> (256MB, PC133, CL2, 32Megx64) for a T21 (type 2647), which is what I
> have. Are crucial wrong here? Does only a subset of PC133 memoery work
> in it?
>
> I am in the market for a 256MB stick as the existing 256MB doesn't get
> you far these days. Ebay is much cheaper than crucial, but it sounds
> like it's easy to get the wrong stuff for this model.
>
> I note that PC100 256Mb is somewhat more expesnive than PC133 256MB,
> but obviously I'm happy to buy it if it really is necessary.

While the T2x thinkpads are generally pretty finicky, the speeds are
not really an issue per se.  It's the number and density of the chips
on the dimm that cause problems.

Alex

>
> Wookey
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