my hp media centre pc config is
PentiumD 820 (S) DC 2.8 GHz
800 MHz front side bus
motherboard name: Asterope2-GL8E Chipset X200
2 GB DDR2 ram 667Mhz
Hard drive 160 GB SATA 7200 rpm
GeForce 7300LE 64 MB DDR memory
300W HIPRO smps with 19A on 12V Rail
i am upgrading my gpu to 512 mb hd 4670.
do i need to change the power supply.
i also have on tv tuner card, one lan card, and one more pci card. i am planning to remove the latter two as i am not using them.
i also have a coolermaster fan/heatsink other than the fan which comes with the pc.
The modern equivalent of a PD 820 would be a C2D X6800, they're not that power hungry when running stock. Only when overclocked.
'HIPRO' has made cheap bundled PSUs in that past e.g. not capable of outputting rated watt. Mostly made before 2006. They probably have minimal labeling, standard grey paint (or worse, zinc plated) and have fan grills that are part of the enclosure.
Otherwise 300W is more than what's needed here. The power efficiency of PD 820 is bit of a concern tho if running 24/7.
This is a handy little ready reckoner for working out your PSU requirements. Given the age of your PSU, if you find that the amount required gets over about 225w, I'd look at getting a new one. It's cheaper in the long run than replacing anything else if your PSU blows and takes any other components with it.
I suppose that PSU mighnt bt O.k, but I wouldn't do it. I think a 9500GT would be a better choice for you as it uses less power than the 4670. Even though it is significantly slower, it probably wouldn't be too much slower on your PC since the 4670 would be held back by your CPU anyway.