ATX 450W PSU is NOT actually 450W??

Hi there,

I recently bought a lovely tower with great specs and 'what I thought' was a 450W power supply. It came with a 6450 graphics card which is good but not good enough for my needs so I got my eyes set on the Radeon 5770 which requires a 450W power supply.
Only thing is I spoke to the guy who put together my system and he said even though my PSU is a 450W, it doesn't actually give out that much power? And if I wanted to upgrade my graphics card i would have to upgrade the PSU.
Does anyone know what the guys trying to say?
Is there such a thing as a "real power" PSU?
Any recommendations on what PSU to run the graphics card?

I know to some this might be an easy question but I'm quite new with these things.
Thanks for your help.

Chris :bounce:

ps. heres my system specs:

Processor (CPU): AMD Bulldozer FX-4 Quad Core 4100
3.60Ghz (3.8Ghz Turbo Mode)
4 CORES Black Edition Perfect For Overclocking
Motherboard: ASUS M5A78L-M USB3 With AMD 760 Chipset
Supporting Quad & SIX Core CPUs & DDR3 Memory
Memory: 4GB DDR3 1333Mhz PC10666 DUAL CHANNEL KIT
Hard Drive: 1TB SATA2, 7200 RPM
Optical Drive: SONY 24XDVD+/-RW Lightscribe & Dual Layer
Graphics Card: ATI Radeon 6450 1GB Graphics Card
Direct X11 With VGA, DVI & HDMI Outputs
Case: COOLERMASTER Elite 330 Black Tower Case & 450W PSU
Connections: 8 x USB2.0 Inc 2 USB3.0, Gigabit LAN 10/100/1000 & 7.1 HD Audio
1 x PS/2 Ports, 1 x Optical S/PDIF Port
8 answers Last reply
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  1. There are power supplies that are rated at say: 650w, but in reality can only output 450w. Such as Raidmax and cooler master gx power supplies. Companies you want to buy are corsair, antec, seasonic, and xfx. What is your budget for a power supply? Are you planning on running crossfire?
  2. Crossfire is something I might look in to one day but for now I just want a half decent graphics card like the 5770 to run games like COD and Old Republic.
    I have seen many PSU's for cheap on ebay but they look dodgy and might just be the same as the one I've got. My budget is around £40 I guess..
  3. Corsair cx 500w.
  4. Excellent thanks for your help.
  5. He was probably referring to the fact that the psu is 450W max power output not continuous.
    I'll assume it came with the case and if it's a CM Real Power unit = old inefficient design without a PCI-E 6pin power.
    He's giving you good advice.
    What's your psu budget?
  6. Your right it did come with the case and it doesnt have a 6 pin PCI-E. Your suggestions are great thank you. I always knew he was giving me good adive :P
    The Corsair looks like a good one for me.
  7. For powersupply info in future, check out jonnyguru, great psu review site
    and the CX500 is a great little psu,
    as well as amazon and egay to find the best price :)
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