[Solved] ATI 4770 CF vs 5850

I am planning to upgrade my system to increase gaming performance:

CPU: AMD Athlon II x3 435 (triple core 2,Ghz) although I am not intersted in changing it CPU right now
Motherboard: Asrock N-68S
GPU: XFX Radeon HD 4770
Power supply: 550W with 2x 6-pin PCI-e Connectors (I do not know the name)
RAM: 2x Kingston 1GB DDR2 RAM

To be brief I am currently trying to decide between 4770 CF and 5850 But there is a problem:

my motherboard is not crossfireX compactibe, so I am going for the 477 CF I`ll have to change motherboard. I could get an MSI 790XT-G45 for about 100$. If I go for the 5850 I won`t need a new motherboard at all and I would get DX11, but I really need those 2 extra RAM slots plus some other features and extension slots that my current motherboard does not have.

Price of 4770 + new motherboard should be about 210 $
Price of a single 5850 would be 300 $
The performance of 2x4770 should be almost equal to a 5850. If I go for with the CF 4770 I will save some money and increase RAM and I get a CrossFireX compactible motherboard

By the way, my monitor does not support resolutions higher than 1280x1024

Absolutely no point in either CF4770's or a single HD5850 as both are completely overkill for your system.

A HD5750 or HD5770 is more than enough + Your CPU will bottleneck even a HD5750 so it would be completely pointless to get anything better

Oh yeah, if that PSU isn't a particularly good brand then crossfiring even a rather low power card like the HD4770 might be asking a bit much from it.

That was helpful but I am still considering upgrading my motherboard as it gives me more upgrade options especially crossfire X capability which would be very useful whatever card I decide to buy

My 4770 is good enough for now, so there`s no need for me to replace it immediately. I`ll wait until I save more money to buy a better card and a new monitor (and a power supply if I really need it)

Well ideally for a new motherboard you will want the latest chipset which is the 890GX;
http://www.newegg.com/Product/Prod [...] geSize=100
It is DDR3 however so you will have to ditch your current ram. I'd recommend one that says USB3.0 so you have the latest standard for everything. Also with some of these boards you can attempt to unlock the fourth core of your processor so you may want to look into which ones are capable of such.

The point of unlocking the core is to see if it is defective. If not there's no reason not to use it. If it is you'll want to turn it off again. Some of those chips are even a Deneb(Phenom II) core and the extra cache can be enabled as well. This feature isn't exclusive to the 890GX so you can get a board that can let you do so even with the older chipsets.
The price difference is between DDR2 and DDR3 is fairly small at this point. As for the performance difference if you get some DDR3 1600 with good timings the performance difference should be 5%+ I believe.
The new chipset also uses SATA III(6 gb/s) while the others use SATA II(3 gb/s)

I decided to get a motherboard with DDR3, USB 3.0 and DDR3 RAM as described above although I have not decided on any specific model yet

I am rather confused about the power supply. In all power Power Supply Calculators I`ve tried the total power I need resulted being within 550W even at full load and my power supply is almost new

What do they cost new there? $85 seems like a bit much for a used HD4770.
The problem with your power supply is that it is a very poor brand. Like I said earlier that amperage on the +12v rail is very low for a 550w(+12v is what video cards use for power.) For an example here is a 380w PSU from a quality manufacturer;
http://www.newegg.com/Product/Prod [...] 6817371033
It has 32 amps on the +12v rails, much higher than yours despite the supposed 550w rating and I wouldn't recommend crossfiring with that PSU either.

Ok, F. it I`m going to get a job next month as soon as I finish exams. And with the money I`ll earn + the ones I`ve saved I`m going to buy some high-end components
Power supply + motherboard + RAM
And a monitor of course I have any money left