Upgrading my GPU

[Sakisman]

Hello guys, i am new in this awesome site and i would like to hear your thoughts about which graphic card will be the best upgrade for my pc. These are my computer specs:

Motherboard: Gigabyte GA-MA78LM-S2H
CPU: AMD Phenom(tm) II x4 925 at 2,80 GHz
GPU: ATI RADEON HD 5670
RAM: 4,00 gb ddr2
Power supply: 600W
Windows 7 64-bit system
1920x1080 resolution

I want to play skyrim/bf3 at high/ultra settings without problems. I dont know much about overclocking so i am not going to overclock my GPU. I heard from commects that for bf3 nvidia is better for game performance and drivers, but at high resolution (not sure how high) others say that AMD card 7850+ are better, same as overclock. I have searched a lot of sites for GPUs and i believe a Sapphire Radeon HD 7870 GHz Edition OC 2GB GDDR5 will be a good choise. Feel free to correct me and plz advice me which graphic card will be good for me. My budget is about 350-400 euro.

Thanks in advance.

 

[Sakisman]

I know i didnt write important things about my pc (motherboard) but could someone plz link a good program to scan my pc for all the details?

 

[DavidY]

I know i didnt write important things about my pc (motherboard) but could someone plz link a good program to scan my pc for all the details?

Belarc Advisor, PC Wizard 2012, etc.

What is the make/model of your power supply?

Dave