I am not building a pc at this moment so there are no other specs just the cards.
Is there any noticeable difference in speed with graphic card with the same chip and different manufacturer?
Ex. hd5770 chip 1GB and prices, in Finland, between 180 dollars to 270 dollars, cheap end club 3d, sapphire and xfx, middle msi, HIS, asus, xfx and expensive end we have msi and powercolor.
There are of course different connectors and so but what makes one card better than the other or one card worse than the other.
Is a card with a "box" around better for keeping the rest of the pc cooler?
Last question. Why spend almost 300 USD for a card if you can get the same, or almost the same, for 180 USD?
In the USA, we don't normally see such radical differences in pricing for the same card from one manufacturer and another. There are differences, but not like that.
All the reference design cards made by the different manufacturers are the same physically (more or less). The main difference is warranties and customer service when things go wrong.
Non reference designs may have better cooling and or factory over clocks, some have different amounts of ram as well. Better cooling often can mean a quieter system or allow you to overclock the card yourself with more success. Generally any factory over clock can be performed by yourself, so it's not usually worth buying for a factory overclock.
I'd go for the 180 card over the 270 card if they are basically the same. You might be paying extra due to shipping or government fees for buying from certain countries that the cheaper card doesn't have to deal with.