Noob lf build advice. (Components)

[spiritmoo]

Hey there!
Getting straight to the point:
HDD - 1TB Western Digital Caviar Green, SATA II
RAM - Corsair 4GB (2x2048MB) 1600MHz XMS3
PSU - Fractal Design Tesla 650W 80+
GPU - Gigabyte Radeon HD5770SL 1GB
CPU - AMD Phenom II X4 965 3,4GHz Black Edition
MOBO- Gigabyte GA-890GPA-UD3H

This is my current build, and I'm wondering if these parts will work good together.
Also, will there be a big difference in buying a "Gigabyte Radeon HD6850 OC 1GB" as my GPU instead of the 5770 one?

Last question is about the cases; Which one will perform best/suite all the pieces best? I'm thinking of "Cooler Master HAF 912 Plus",
"Cooler Master 690 II Advanced" or "Cooler Master Centurion 5 II".

Sorry if this made little sense, I'm awful at computers.

 

[mihir]

The performance would increase significantly.Using the 6850.
As for the cases I would go for a bigger case like the Coolermaster 922.
and out of those the 912 would be good enough

 

[daisymtc]

No sure the brand of PSU.

 

[spiritmoo]

Alright!

Is there a difference in performance between the "Gigabyte GA-890GPA-UD3H" and the "MSI 870A-G54"?

MSI 870A-G54 - http://www.newegg.com/Product/Product.aspx?Item=N82E16813130275

GIGABYTE GA-890GPA-UD3H - http://www.newegg.com/Product/Product.aspx?Item=N82E16813128435&Tpk=Gigabyte GA-890GPA-UD3H

 

[linkin]

I'd grab the gigabyte board. I don't trust MSI anymore after the exploding VRM's stories...