Be aware that Crossfire provides usually no more than 75% improved performance at the best of times and often no more than 40% or so (it really depends on the games).
It's also important to have a CPU that can handle the added card. To test this:
Hit CTRL-ALT-DEL, then leave the Task Manager running. Change settings to lowest update frequency. Now open a game and play for several minutes.
Leave the game and note your CPU history.
If your CPU is regularly going above 70% then I can't recommend a second card for Crossfire. (it's difficult to estimate now that we have multi-core setups as the game might not support all cores. You may only be able to get one core to 100% by using a better card or you may be able to get two cores fully and two cores partially.)
There are ways to make the game perform much better (better FPS). Anti-Aliasing is one way. Instead of 8xAA go with 4x. Turn down shadows. Experiment. Run FRAPS at the same time or better yet use a benchmark tool like Crysis has.
The higher the resolution of the monitor the LESS the need for AA (which eliminates jagged edges). A monitor like the new 27" U2711 with a resolution of 2650x1440 probably needs no AA and freeing up that extra horsepower can help compensate for the added resolution.
There's lots of tips for getting the most out of your computer for games.
Runs below 50% all cores. temperatures are 21 degrees processor / 37 degrees system.
Next Question is that power supply may need to be replaced or maybe not it puts out 43A 12V rails (2) so about 520 watts max give or take. I think that puts my system jus at the mark to run crossfire? what do you think?
Yeah I upgraded to the Antec 650w PSU and Yes you can crossfire HDMI but I had a problem at first because you still have to go to the bios to tell which card you want to be the primary display adapter. At first couldn't get a picture cause i had it connected to the new card and when i connected it to the old card it worked like a charm.