so i have this 500 watt PSU http://www.newegg.com/Product/Product.aspx?Item=N82E16817171031
athlon II x2 @4.0GHz and a 4890. i have to use a molex to 6pin to make my card work. i want to upgrade to a quad but im scared the the quad and the 4890 will suck up too much power. i could upgrade my Gpu and that would take less power, but then i wont have enough money for a new cpu. what should i upgrade in this situation? i have a max of $150 budget
For $150 you won't get a GPU that's much faster than that Radeon, whoever it will use a lot less power.
I'd personally upgrade the CPU to a Phenom II X4 and if you're worried about the PSU get a new one from the remaining funds. Phenom II X4s are around $80-$100.
Thanks for the reply. thats what i was thinking of. I max out all the old games such as crysis 1, call of duty 5, and ect. but newer games are using engines that use quads and they just eat my dual core. so i thouht a quad would help a decent amount.