Help me choose a better graphics card

If you currently have 5830, upgrading to 6850 will not be worth in my opinion.
What is your budget ?

At the moment, budget is not my problem. However i'd love to save money if possible  

Speaking of which how much performance difference do these cards have? 50% ?? o.O

7850 or 7870 would be a nice upgrade

50%?
No not at all
It would be good if you can mention your budget.
Anyway, 7850 is very value for money and is a very nice upgrade (as mikem suggested)

7979 and your set  
Best value for money.

Alright that's fine but i want to know how much performance difference will i be getting or i'd see if i opt for this card?

I did comparison today between MSI R5830 1gb ddr5 and Sapphire AMD radeon hd 6850 1gb ddr5

Now here's the deal, i tried the evaluation test on two games. 1st it was risen 2 on ultra settings and 2nd was skyrim ultra settings.

Now here's the funny thing. we all know that 5830 is a weaker card. However it performed well in rendering graphics lightening and details and on the other hand i felt 6850 was able to push more to framerates and had more frames per second, but to eyecandy lovers i found MSI R5830 beats 6850 easily. 6850's lightening(sunlight) was kinda lame but R5830 was fully bright and looked lively.

Now what i don't understand is why the hell it is like that? why? o.O

OS win xp sp3
4gb ram ddr 3 1333z
amd fx 4100 3.6(stock)

I guess i am seeing things, maybe 6850 is slightly better  

I just restarted my system and tried playing these games once again. it was my bad after installing its drivers i hadn't restarted it my bad. now its performing pretty good. earlier with 5830 i was getting 30-50 fps on ultra settings now i am getting 60-94fps avg. and lightening has improved a lot after i restarted my system.