I'm currently using 947/1250 for a R9 290 Tri-x for 825 KHash.
Kind of disappointed, I could have got a 280X almost at this hash rate.
Although it's been around 25 degrees in Auckland (NZ) lately, even wiath fan at 75% my GPU temp gets to around 82.
Why did you down clocked it?
some Sapphire R9 290 Tri-X won't run stable if you run it with 1000/1300 when using SCRYPT algorithm. Seems like a fault in some batches.