If I get an AGPx8 card but I have an AGPx4 slot will it use less power?

Hey Guys

First post, and not a frequent user of forums, so if I screw up/take a while to respond I've likely got lost and probably been sold a Mac in my confusion

Jokes aside, my question is pretty simple... but a little background...

I have a Dell Precision Workstation 340 Mini-tower:
http://support.dell.com/support/edocs/systems/ws340/en/ug/1specs.htm#1065067

A pitiful 250w PSU... currently have 32mb Quadro2 MRX/EX...
wanting to replace the graphics card to play:

Doom3,
F.E.A.R 1 (+2 if I can),
The 2/3 Newer C&C's etc,
Hitman Blood Money,
and a few others.

I don't want to be replacing the PSU or even upgrade my 512mb of RDRAM as my box is on it's last legs and I see no point as I'll be building my first machine in 6 months.

So with that said...

I have an AGPx4 slot and terrible PSU(250w) so I thought perhaps, just maybe, since a x8 will be knocked back to x4... it may be possible it will use less power in the process.

Is this correct? If so, would it be enough to make a fair difference on my choice of card? (<£50) Or would I be stuck with say a Inno3d FX5200 256Mb?

Cheers.

No, it will still use as much power, just the speed will be less.

What kind of setup are you building in 6 months???

it is NOT worth spending any kind of money on that system.