Upgradeing my lx6200

[supermalibuZ16]

i have looked at a few upgrade parts .. and i need to update my computer to play fallout3.. i cant at this time. i got a 2.2cpu and asked for a 2.4cpu or better. and just need a video card. so i looked at newegg. they recomend amd965 b.e./xfx5850- im looking at xfx 5770 to start. o yhea im going to need a 750w psu.i got 1 im looking at too..from ultra /bronze. some say about am2+and am3+processors.well as long at it fits and works to get fallout3 going .so im looking for a mid system upgrade.

 

[enzo matrix]

This computer:
http://support.gateway.com/s/PC/LX/LX6200/LX6200sp2.shtml

Although the chipset of that motherboard will support up to phenom II x4, only support to phenom x4 is listed on gateway's site. Manufacturers have a tendency to not release bios updates for support of newer CPUs, so getting a phenom II or athlon II will be a gamble. So my recommendations:
If you like to gamble:
http://www.newegg.com/Product/Product.aspx?Item=N82E16819103674
I recommend this over the 965 because it is also a BE but costs much less making the 965 not really worth the price. Plus if you want 3.4GHz like the 965, you could just up the multiplier.

If you don't:
http://www.newegg.com/Product/Product.aspx?Item=N82E16819103286
This is a black edition and at a pretty good price because it is older.

Both will be more than fine. You'd even be fine with an Athlon IIx3 440.

As for the GPU,xfx is a good bet because of their double lifetime warranty.

Yeah you will need a new power supply but 750W is overkill. Even if you were to put a 5870 in that computer, you wouldn't need more than a good 500W. I'd say look at the 500W corsair or the 500W OCZ modxstream. Also, do not pay attention to power supplies that say they support this and that i7 or am2+. Of course they support them. It's a power supply. All power supplies support everything. It would be like me saying I can drive a ford sedan on an application to become a taxi driver. Of course I can. All sedans require the same input from the driver.
I also noticed you said "at xfx 5770 to start". You forgot to tell us where you were going with this. If you intend to crossfire a second 5770 down the road, it will affect your power supply choice.