Windows 7: PSU problem, 450W enough for RAID5 server?

I have 2 systems, my server (650W Corsair PSU) and my everyday one (450W Corsair PSU).

I recently upgraded the GFX card in my everyday one to a Powercolor HD 6870 after the guy promised me it would work with my 450W Corsair PSU. My system now becomes unresponsive and the screen displays nothing but blue stripes when I try to watch YouTube videos and such. So I guess the guy was wrong.

Now I have two choices:

1. take the card back and get a 6850 (minimum recommendation from AMD is a 450W PSU)
2. swap the PSU from the server and everyday computer

Since I need the graphics update (a budget level 6870 as I will probably upgrade the entire rig in 2 or 3 years), I am inclined to swap them but the stability of the server cannot be compromised.

My server has 6 1TB SATA2 Spinpoints in RAID5, one IDE bootdrive, and a XFX HD 5450 1GB.



Will 450W be enough for the server? Or is there a better course of action I have not seen?

Googling says that this system:

HIS Radeon HD 5450 1GB GDDR3 Video Card
Processor(s): Intel Core i7 920 @ 3.8GHz (190MHz x 20)
Cooling: Noctua NH-U12P (Supplied by Noctua)
Motherboard(s): GIGABYTE EX58-UD5 (Supplied by GIGABYTE)
Memory: 3 X 2GB Kingston Hyper X PC3-16000 2000MHz DDR CL9 (Supplied by Kingston)
Hard Disk(s): Western Digital 640GB SATA 2.0 HDD (Supplied by Western Digital)
Operating System: Windows 7
Drivers: ATI Catalyst Cedar Beta

uses a little over 200 watts at idle and under 250 under a load.

The extra drives you have might use 6 or 8 watts each.

I'd say you are OK.

thanks, guessed it would have been okay, but thought it was worth checking before I took it apart.

Going to put the 6870 into the server first to see if the card is faulty or not. I would have expected to see issues in my everyday computer under or near full load if the PSU was too weak, not just watching a couple youtube vids.

an update

Installed the 6870 into the server, Windows found the drivers and installed them. Was working fine, playing full HD movies.

I then went to the ATI website and downloaded the latest drivers, rebooted the computer, immediate failure once I tried to play the same movie.

So the AMD Catalyst thing is buggy? So what drivers should I use cause the generic windows one is probably not the best!