You get good performance with 512Mb and if there is a problem you can put in a fixed
paging file.
I misread it the first time and looked at the 4600 on the Crucial (RAM) site ...
arrg!
System Information for the
Dell Dimension 4600
System Type: Desktop Computer
Maximum memory: 4096MB
Standard memory: 128, 256, or 512MB removable
Slots/banks: 4 (2 banks of 2)
So if you have one slot with 256Mb just add another 256Mb and all will be well.
I paid about $50 for a 256Mb module.