You have a x16 slot.
You have a 550 psu.
You could spend some serious bucks and fit in a whopper vid card.
Give some thought to that I3 cpu you have.....it's going to be a bottleneck.
Maybe look at this list and pick some middle of the pack card and hope you have enough cpu horse-power to feed it.
I recently purchased a new computer from a big box store. I am fairly good with computers and when I decided I would like to upgrade the graphics from the Radeon HD 4350 it came with to something much more powerful I did some research. I have since upgraded the power supply to a 550 watt, and the ram from 4 to 8 gigs. I am wondering if the motherboard will allow for a top of the line graphics card. Something like a radeon 6550 or along those lines. I contacted HP but they provided no assistance. The computer model is a p6342f Pavilion. The ram and power supply have been updated. Can anyone help me with what my options for best graphics card I can fit in the system are?