[ltp] TP 600 and Memory

[Tino Keitel]

On Thursday, 27. September 2001 05:20, Adam M. Bodnar wrote:
> I've recently acquired a ThinkPad 600 and been reading up on the specs of
> it and what I'll have to do to get linux running on it.
>
> One of the things I noticed is that it's using a 430TX chipset and from
> what I've read, this chipset can only cache up to 64MB. So least under

I looked into the technical reference of my TP 765L (Pentium 166 MMX, Intel 
430MX). It mentions that the cachable area (we speak of the Level 2 cache 
here) is 64 MB. Have you looked for some sort of technical reference for your 
TP 600?

> Windows, if you have more than 64MB of memory you actually lose
> performance.

You will lose anyway if you are under Windows. :-)

>
> What I was wondering if anyone knows if this behavior occurs under Linux
> and how much memory most people have in their laptop.

It _does_ occur under Linux. I have 88 MB in my TP. Once I booted with 
mem=64m to work around this performance drop, but all I can say is that the 
better performance only showed up in some memory intesive tests (gcc compile, 
mp3 decoding), so I thougt "uncached RAM is still faster than swapping in/out 
from/to hard disk" and continued with 88 MB. Maybe the difference will be 
bigger with a faster processor, but I don't think so since the clock speed of 
the external L2 cache is independent from the CPU clock. I'm sure it _will_ 
be bigger if you have more RAM. With 88 MB, there are 64 MB cached versus 24 
MB uncached. With 192 MB, there are 64 MB cached versus 128 MB uncached.

Tino

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