|According to Crucial.com:|
"We've calculated the maximum memory capacity that your computer can handle per slot and matched it with our guaranteed-compatible parts to give you our max it out recommendation."
""Each memory slot can hold SDRAM, PC133 with a maximum of 512MB per slot."
"Maximum Memory: 1024MB
Slots: 2 (2 banks of 1)
Standard Memory: 128MB removable
USB Support: 1.x Compliant"
Dell abandoned this old system a LONG time ago & I'm sure hasn't bothered to update it's compatibilty list in years. I'd take Crucial's recommendation over Dell's.