i have one doubt .my friends say asus board is better than asrock. Is it true?
Used to be true - not anymore. Asus is now just overpriced. I like ASRock because it's good quality with a great feature set at a good price.
I selected a 970 chipset, newer gen but not as expensive as a 990FX. This ASRock board has more memory capability, has a lower percentage of negative reviews, has a better sound chip, and costs $15 less than the Asus board.
The I5-4430 is the lowest end I5, so it's marginally better than the FX-6300. The 4430 will be better for single threaded performance by about 25%, but the FX-6300 will be better for multi-threaded applications.
If you are up for a little over-clocking, then you can tweak the 6300 up so it matches the 4430 single-threaded performance and exceeds it in multi-threaded.
If power consumption is a concern, then the I5 will run with less power, especially when you consider over-clocking the 6300. But the real $$ cost is not significant unless you're running something like folding at home 24x7.
For gaming, the 6300/7850 combination will be much better than the I5/7770 combination. The 7850 is a great mid-range GPU that will run almost anything except the latest titles on high/ultra settings. But even the 7850 is getting a little stretched for the latest titles like Far Cry 3, where you'll need to step down to Medium settings (you need to spend ~$250 for a GPU that runs Far Cry 3 on high).
The 7770 will run everything but the latest titles probably on medium settings, and latest titles will be almost un-playable, except at the lowest settings. But for older titles or more casual Steam games, the 7770 is fine.
I'd recommend you go with the build you're most comfortable with. If you want to play a little with your PC, and get maximum performance for the $$, then I'd go AMD. If you're not really up for that and just want something you don't hassle with, and something that runs a little cooler, then go for the I5 build.
Either build is a great build for the $$, and so just go with your gut and run with it.