I can't answer your question. Mostly you didn't list any specs other than the GPU. The resolution, CPU, RAM, and OS are all important.
This article was right on the front page and you can see for yourself what frame rate you'll expect at high settings - http://www.tomshardware.com/reviews/skyrim-performance-benchmark,3074-5.html
Just look at the 5770 and assume you'll be down a few frames per second.