My computer has 2 RAM slots occupied by 2x 512 MB RAM cards. I want to upgrade my RAM. would it be worth getting a 1GB RAM card and adding it? will i see a significant difference between 1GB and 1.5GB? I dont have much money atm, so buying 2Gb of RAM isnt really an option, and i want to know if it will be a waste of my money to but 1GB

Yes if you are talkingabout thumb drive cards. You're better off getting another 2x 512mb of ram.

If you add the same type of 2X512 MB sticks as your current RAM sticks, that may be beneficial because you may continue making use of dual channel operation if your M/B supports it. Otherwise you break dual channel operation if you add different size and timing RAM sticks even though your M/B supported it.. Regards suatcini

i only have 2 RAm slots, so iwas wondering if i replace one of the 512 MB RAM cards with a 1GB one, will it be worth the money, or do i have to get 2x 1GB RAM

Of course, every addition of MB will be helpful, but you may break dual channel operation of your system if you have different size RAM sticks in the slots, which will sure degrade the performance of your system noticeably and more than offset the addition of extra megabytes.. Therefore, check your M/B manual if it has dual-channel capability. If it does, stay with the existing configuration or upgrade both 512 MB sticks with 1 GB sticks. Otherwise you can replace one 512 MB stick with 1 GB stick. Regards suatcini