Your Dell Dimension 4600 only supports modules made with a specific type of chip. Should you find what seems to be the exact same memory elsewhere for a lower price, it is very possible that the cheaper memory will not work in your computer.
Brand:Manufactured by Major BrandType:DDR1 SDRAMMPN:CM128643200D1X2Form Factor:DIMMNumber of Pins:184pin NON ECC
DIMMBus Speed:PC3200 (DDR 400)Density:Low DensityNumber of Modules:2Memory (RAM):2 GB (two identical pcs)Capacity per Module:1 GBNumber of Memory Chips:2pcs
Made from the highest quality components, GatewayTech memory modules from
Arch Memory are designed to increase productivity and help your computer work faster. Arch Memory products are engineered to meet industry standard specifications and rigorously tested to ensure quality. ...