Ati radeon, stick with 5670 or upgrade to 5750

if you are upgrading from a 5670 I would at least upgrade to a 5770 or more bc honestly a 5670 to a 5750 is not worth upgrading too imo, those chips are not even fast enough to make use of 1 gig of ram. If you want to upgrade I would at least get a 5770, but for the money I would get a 768 mb or 1 gig gtx 460, or maybe a 6850 (depending on what your res is). Anything less is not worth upgrading to in my opinion and especially not worth upgrading to if you are play at low res so lat me know... What are your full system specs? What is your monitors resolution? and most importantly what is your budget?? upgrading to a 5750 froma 5670 is not worth it imo

There is little to no performance difference between the 512k and 1gb versions of those cards, don't waste your money upgrading to a 1gb card at that level. The 5750 is faster than the 5670 but not enough so to make it worth upgrading to that either IMO.

if you want a cheap upgrade and dont care about dx11 (i dont see how you can utilize it much at that level of card) go on ebay and grab a 4870 or gtx 260 which will be on par with the 5770 and can probably be had for around 60-70 dollars it would be a decent upgrade but not a huge one. However without knowing your full system specs I can't really recomend much beyond that.. especially knowing what psu and cpu you have...

System spec...
Windows: Windows 7 Ultimate Edition
Memory: 2GB of DDR2 800MHz (going to buy soon 4 if it is worth)
CPU: AMD Phenom II X2 550 processor 3.1 GHz
Display: Ati Radeon 5670 512 mb ddr5
Monitor resolution: 1680 x 1050
Motherboard: Gigabyte Technology M720-US3

My budget is around 130-150 euro, the 5770 costs here around 153.

what is the make and model of your psu (power supply unit)?? sorry if I sound redundant just clarifying, without that info I can't recommend anything... if it is sufficient I would either get a 5770 or grab a 4870 or better off ebay for 60 bucks or so and save your money if that is all your budget will permit. So let me know about the psu make and model and I will get back to you

Gigabyte superb 550P
450W Continuous Output
550W Peak Combined Wattage
ATX 12v 2.3 & EPS 12V

yeah a 5770 should work but your psu is a little suspect to be honest, I wouldnt try to run anything of a higher power draw than that. You will need 1 pci-e 6 pin plug from your psu and if not a molex to 6 pin adapter. Is there a site that you prefer to order from in the UK?

Well the problem is there is no country that delivers it to Bosnian  
I could give you a site with the cards so you could look at them if you have time  

im off work today so....yeah send it on over! would you consider a psu upgrade? because that will open up your options a lot... in short, a 5770 should be good at 1650X1080 but not great but let me know what you can work with as well as the site for bosnian comp parts...also you need to get another 2 gigs of ram it is definatley worth it and you should be able to find some secondhand ddr2 or at least cheap somewhere perhaps

http://www.plus.ba/proizvodi/index.php?idkat=693

http://ingel.ba/ingelshop/category.php?id_category=17

so yeah these are the two sites, to convert the money in euros just cut the half price down, also a PS upgrade would be possible in the near future  

VGA GIGABYTE ATI HD5770 GV-R577UD-1GD 1GB DDR5/128bit DUAL DVI HDMI

yeah you want to go for something like that or get a new psu and get something like a 6870 or gtx 460

That 5770 will match up well with your system.

I recommend the HD 5770 for your setup.

i think the 5750 is a fair bit faster than the 5670, but yes the 5770 is better again. heres a comparison between the 3 http://www.tomshardware.com/charts/2010-gaming-graphics... you should also consider a nvidia gts450 which is a bit faster than the 5750