There is no need to triple post here, please don't litter!
The memory managment in linux is a different beast than the one implemented in the other OS's. Linux makes use of your memory, and most of it buffered anyway. What do you mean by "slow down its response"? Have you check your memory for memory leaks, the best checker is http://www.memtest86.com
I just can imagine how long it will run for 2G of memory.