Scrypt is the realm of ASIC and has been for years - you need to reconfigure your miner software to use skein or groetsl (if either of those work on AMD hardware, you might need a different miner version).
There is NO BLOODY WAY you were getting an actual 3+ Gh/s scrypt mining rate from any GPU, I'd estimate a R9 390X actual Scypt hashrate would be closer to 1 Mh/s (perhaps a little over).
haha ya i was like this doesnt seem correct and so i will go to skein or groetsl and see if that works and hopefully that does and see if it reads on the website. cause once that works then i know i am good
If you go groestl use sgminer, get the updated kernel. I dropped memory clocks on the cards as low as they would go, upped GPU clocks as high as they would go on stock voltage. I've not messed with skein.