ATI HD 5830 1GB DDR5

I'm assuming the price is so close simply because the 5830 is an outdated product (I'm in the US but I've seen some pretty great deals on them). The 5830 is significantly more powerful than the 5770, but it is basically a stripped down 5870 so it uses a lot of power for the performance (about 40% more than the 5770 while getting 15-20ish % better performance).

Here is the review of the 5830 from Tom's- the benchmark games are a bit outdated, but it should still be helpful:

http://www.tomshardware.com/reviews/radeon-hd-5830,2564.html

Yeah, it's like that over here too. It isn't outdated though. It just isn't top-end.