[ltp] Thinkpad 600 and maximising RAM with success

[wes schreiner]

Daniel Schmidt wrote:

>Hi List,
>
>as Notebook S0-Dimms (SDRAM) are quite cheap at the moment, i tried to upgrade my Thinkpad 600 (2645-510) from 224 MB to 288MB, which is the maximum of RAM for that model.
>  
>

I've been doing something similar recently for my 600E.  It has the same 
memory arrrangement as the 600: 32MB onboard, and two slots that can 
have a maximum of 128MB in each, all PC-66.  When I received the 600E it 
had a 64MB PC-66 and a 32MB PC-66, for a total of 128MB with the onboard 
32MB.  I swapped the 32MB PC-66 with a 64MB PC-100 SODIMM that came out 
of a newer Thinkpad to get 160MB and all was well.  Recently I bought 
two generic 128MB PC-100 modules.  When I installed them the initial 
screen would show 288MB but the computer would freeze at that point, so 
I put the old modules back in.  When I read Daniel's message about one 
slot needing to be PC-66 I tried swapping the 64MB PC-100 with one of 
the new 128MB PC-100 modules.  This time it booted, but Linux soon 
oopsed!  I rebooted with a memtest-86 floppy and sure enough, got many 
errors starting at the 32MB point.  I swapped the 128MB PC-100 for the 
other 128 MB PC-100 module I had, but same story.  I put the 64MB PC-100 
module back in and now memtest-86 reports no errors.  The working 64MB 
PC-100 SODIMM is marked as being CL-2, and I bet that the generic 128MB 
modules are CL-3 and that's why they fail the memory tests.

Moral of the story:  Not all memory is created equal, so ALWAYS run 
memtest-86 after changing memory.

I already have a pair of 128MB PC-66 CL-2 modules on order from Crucial 
and while I have never had a problem with Crucial memory I will 
definitely have memtest-86 do its tests just to be sure.

wes