Bought 2 of these, took a while to arrive, due to the Easter period.
Nevertheless, removed my 2 x 512Mb slot and put in the 2 x 1Gb slots and have seen a modest improvement on Desktop PC with Intel Celeron D, 2.93GHz, Windows XP
I bought them when they were selling for £17.99 each...which lasted for about 2 days and have since gone back up to £32.99, so i got a bargain
If your wanting to buy these, bookmark the webpage and keep checking back and buy when there £17.99 definetly work it !!!