Clear Cache in Mac OS X might increase fast bootup

Last week I went to a service center to ask why my Mac book is slow only while booting. One of the suggestion was that RAM present in the Mac to be increased which might cost little expensive. This was definite but spending money would mean that we need to think really is that needed ? Anyway I also asked him is there any other way without spending money really much. He suggested two ways which help to improve the Mac performance better.

a) To clear the caches

To clear the cache you need to move all the files from /Library/Caches to Trash
Also Move all the files from /Users//Library/Caches to Trash

b) Need to have 60 GB of free space

I have a HDD of 200 GB and 2GB RAM in which 1GB RAM is fully utilized by the Mac Leopard itself. Whenever I have less than 40GB of space, my Mac drive slowly and sometimes i feel its hanged but never.

Hope this might solve you too.