I bought the ATI 9600XT that said it needed a 300 watt P/S. It seems to work just fine with the 250 Watt P/S.

Upgrading from the 250W to a 350-400W should not harm your system in any way.

The higher wattage just means that it is capable of supplying more power at any given time.

The voltage given to each component should remain the same, or become better than what it was.

If your computer motherboard has a program to evaluate the voltages, run it.  Look and see how many times the voltages to any given component is shorted on power that it needs to operate properly. Chances are the 250W is supplying enough to run the computer, but may not be enough to keep it running real well.

An upgrade to a better power supply will give your computer, giving you better, more reliable performance...

Get one up to 450watts if it's around the same price, then you shouldn't have to worry for a while.

You'll need a phillips head screwdriver and 10 minutes spare time.

Be careful you don't bend any connector pins when you put everything back together.

Oh, and make sure it's the same physical size, some of the proprietry PC brands' PSU's are very small units.

I went out on a limb and got a 400 watt power supply that i hope will fit....... Does anybody know what WON'T fit in a Dell 8300?

i just found out that dell has made it near IMPOSSIBLE to change power supplies!!!  The wiring is different than a "home-built" comp.  If anybody was or is in the same boat and knows how to fix this...please help!! 

The wiring should follow current ATX standards, so I find that strange.

The only difference possible is the connector(s) to the mainboard, and maindboard manufacturers are standardised ATX compatible!

I just went to the Dell site for tech support, and they are more secretive than ever, it's now impossible for me to find what mainboard you have.

It is, however, based on the Intel 875 chipset, which is top notch technology, so I am assuming their supplier is going to provide up to date, standardised gear.

Check your source on the compatibility issue you mention above, it may be misleading.

Another way out is to dump the case and get another one as long as the mainboard connectors are standard.

A new case will come with a PSU, specify the watttage when you buy it.

See if you can use your service number to collect as much tech. specs as you can about your hardware, particularly your exact mainboard model, it's important if you wish to buy third party replacements and be free of the Dell trap.

While at the Dell service site, check to see what they have as a replacement.

There is one other sloppy, but very sound solution, get another PSU (a small one will do) and plug it into the video card ( and maybe 1 or 2 of your CDROM drives or a hard drive to share the load with the main PSU. You may need to extend the connector cables to reach inside the case.

The Extra PSU should be an old type (non ATX) or a switchable one, because ATX type is switched by the mainboard connector. (which you won't have connected).

An old computer can be scavenged for it, but it is safer to go to a local PC repairer and tell him what you want, he'll sort it for you. (He/She may modify an ATX type).

Also make sure that you power up the new PSU with the system when you power up, so the video card Posts to BIOS at boot up. (Have the PSU on the same Powerboard as your other peripherals and main PC power).

This has been another Congo Dell Solution    

I found that PCPowerandCooling.com sells power supplies specifically made for Dell cases. *whew* I still want to be sure that the wiring and board are standardised ATX compatible.  I have send an email asking them that very question and have my fingers crossed.  I like the Congo's second PSU idea, but have no idea how I would make it boot up with the system.  It may seem real simple, but then again I am still very new at upgrading and reparing.  All of your solutions seem great, I just don't know if I can trust myself to pull them off   Oh well......maybe PCPowerandCooling.com has just the PSU I'm looking for.  I have my fingers crossed!