Any advice appreciated. I am trying to decide which PSU to get. I am not bothered about getting a that is more powerfull than it needs to be to allow for future upgrades- I have a limited budget and just want one that has enough to power to power my system - I am not bothered about the getting the "best" money can buy. - Just something that will get the job done.
I originally consider generic because I have been using a 500w generic psu that came with my case for over a year but I have been told it better to get a branded psu :
My setup is as follows :
Processor: AMD Phenom II 1055t - 3.3 GHz (Stock Voltage)
HD : Samsung F4 1tb 7200 rpm (I would like to add another hard drive as a primary O/S drive possibly a SSD)
Motherboard : ASUS M4A79XTD EVO motherboard
Graphics : ATI RADEON HD 5770 Graphics card
Case/chassis : Antec 300
Optical Drive: Samsung DVD Burner
I have found to PSU's that are in my price range
OCZ Technology 500W CoreXStream Series Power Supply
Antec 450w VP450P Power Supply
I always run a 500w minimum to be safe (I always build mid-end systems that don't draw much power and only have the required hardware). There's more to a PSU than just the wattage, though, you have to look at the voltage on the 12v rails. If the voltages are too low it'll be unstable and if it's too high it'll wear your hardware prematurely. I'm not an expert on this stuff but I'd say you'd be safe with at least a 500w PSU as long as you aren't running a bunch of extra stuff (dual video cards, extra disks, drives, tons of fans and lights, etc.)
And remember that a lot of PSU's out there aren't actually manufactured by the brand name on the unit; however, they usually have a standard of quality to meet in order to pass and be sold as such.
And I'd suggest getting a modular PSU if you can afford it. It makes it so you plug in only the wires you need for your particular system rather than having to tuck away all the unused ones. The other wires can always be added later if you add more hardware to your system.
Anyways, I think you'll be safe with a 500w minimum as I believe my system requires more power and my 500w holds up great. If a 550w makes you feel safer, then go for it, but in my opinion it's overkill.
AMD recommends a 450W PSU with one PCIe connector for a system with a 5770. This number has to account for people using very power hungry systems (which yours is not) as well as poor quality units.
So you could actually get a lower wattage unit aslong as it is high quality.
Out of the two you listed the Antec VP550P is the better unit, you could actually crossfire 5770s on it. Seeing as you said that you are not interested in this I think you should get the 450W version:
Antec VP450P (£30 @ Scan) http://skinflint.co.uk/584982