psu

Highest on you will find is a 305. Dell labels it a "Performance Power Supply"

Many older Dell PCs contain a propriatary powersupply.The connectors on these powersupplies look like and fit standard ATX connectors but they are wired differently so the voltage produced by each pin is different than a standard ATX powersupply. Replaceing these propriatary powersupplies with a stantard ATX powersupply may result in the PC simply not starting if the powersupply has good protection.The other posibility is that the powersupply will try to power the system and fry components such as the CPU,motherboard,or ram.This mainly applies to Dell Pentium 2 and Pentium 3 systems but some early Pentium 4 Dells are also affected.Dell Systems with a 24 pin connector are not affected
This lists a PC Power & Cooling replacement powersupply for specific dell systems.
http://www.pcpowercooling.com/produc...ector/dell.htm

you can also use a Dell converter to turn any ATX power supply into a Dell compatible unit they are avalible here
http://www.endpcnoise.com/cgi-bin/e/...=dellconverter

Here is a list of some non-effected systems:
http://www.pchardwarehelp.com/Power-Supply.php
many newer models with 24 pin connectors are not on this list but all 24 pin models are not affected