How much RAM does Windows XP need?

When your Mom and her partner drop by with two identical five-year-old laptops complaining of slowness, should you recommend new laptops, or just put in more RAM? Time for an experiment!

The patients were identical Toshiba Satellite A15-S129 laptops with 256MB of RAM and a 2.4GHz Celeron processor.

First step was to remove all the extra crap from the Startup menu, and use msconfig to disable everything else that didn't look neccessary.

Next step was to define a benchmark meaningful to the user. In this case, they use Photoshop Elements 5, so I added the trial version of that app to the startup menu, and measured how long it took from poweron to the license prompt for Photoshop.

I then ran that benchmark with the original 256MB, then with 512MB, and finally 768 MB. Results:
poweron to license prompt404 sec226 sec205 sec
Conclusion: Doubling RAM to 512MB and some minor cleanup sped up the computer by almost 2X, no need to replace the laptop. RAM is cheap, so go to 768MB for that extra 10% speedup.

Here's the detailed data (wall clock time, minutes and seconds):

Poweron:  48:00
login:    48:39
Desktop:  49:09
launcher: 52:09
splash2:  53:06
show pic: 54:24
license:  54:44 (404 sec)

Poweron:  43:00
login:    43:49
Desktop:  44:13
launcher: 44:23
splash2:  44:53
show pic: 46:38
license:  46:46 (226 sec)

Poweron:  04:00
login:    04:52
Desktop:  05:13
launcher: 05:31
splash2:  06:07
show pic: 07:17
license:  07:25 (205 sec)