I have a gigabyte 7790 2G and it performs surprisingly well in titles like Battlefield 3 and 4 and Titanfall, but as the others have said I would recommend getting the newer card. Especially as it has the 2G of RAM. More modern games are starting to max out the 1G cards even with more powerful architecture. I have a GTX 560ti 1G which is noiser and runs hotter than the 7790 under my tests run at home. They perform pretty much the same, infact the 2G 7790 beats the 560 in certain games I have.
Go with the newer card, you won't regret it, it's a good card for the price.