PSU for a casual gaming computer upgrade

basically my question is
will this(has 300W power supply)
HP Pavilion Media Center a1600n Desktop PC - Product Specifications

be able to use this
Power Up 450-Watt ATX 120mm Fan SATA-Ready PCI-E-Ready 24-Pin Power Supply GEN-2005 at TigerDirect.com

in order to power an extra 1gb of ram and this properly
XFX GeForce 8600 GT Video Card - 512MB DDR2, PCI Express, SLI Ready, (Dual Link) DVI, VGA, HDTV, Video Card PVT84JYAJG at TigerDirect.com

Thank you

You could power the 8600 even with the 300W PSU. I would still recommend the 450W incase you wanted to SLI your card or add more RAM and so on…

That’s very, very cheap for a 450W unit. Generally, when it comes to power supplies, you get what you pay for. Power Up! isn’t a well known brand in general, and the price doesn’t give me confidence.

Spend a little more, and you can get a much better unit, like the Corsair VX450. This has been reviewed and does produce the power it claims. It uses a CWT platform, commonly found in Antec and Thermaltake units. Additionally, every Corsair unit you run across has been very well reviewed, and that’s unprecedented.