Just thought you should know... Dell says that you can't put more then 1 GB of RAM in your Dell Dimension 4500 and no Processer higher then a 2.8GHz Northwood--soo not true! You can put 2x1GB of PC2100 DDR Low-Density, Non-ECC, Unbuffered RAM and the BIOS sees it right away, not only that, you can put a Pentium 4, 3.06 Ghz 512k/533 Northwood in it too and the BIOS sees it. The only problem I had is that the Dell BIOS update A04 dose not see the Hyper-Threding tech of the chip. Someone told me that if you have an earlier BIOS it might work or reinstall the op sys it might also work--I'm not going to do that, but if you want to let me know what happens--I'm sure that if the BIOS can't see it then the op sys can't, and do you really want to mess with your BIOS? Very happy with my upgrade, I spent a lot of hours looking into what could be done for this ol' Dell and I've done a great job, not only did I update the mem and the Pentium I also added a FSP460-60GLC 460W Power Supply and a "HIS" IceQ H467QS1GHA Radeon HD 4670 1GB 128-bit DDR3 AGP 4X/8X HDCP Ready Video Card. Whatching HiDef is awsome! No lag as long as you aren't multi-tasking--I don't think it can handle new games, too much to ask, but if you want to make your ol' Dimension kick it up a few notches--go for it!