Litecoin Mining – PowerColor Radeon R9 280X Sweet Spot for 760KHash/sec
If you have read about my early testings on the PowerColor R9 280X for Litecoin mining, you would have noticed that i shared my CGMiner configurations for a hashrate of around 710KHash/sec. Previously, i have mentioned that CGMiner version 3.7.2 with the latest drivers would give you a higher hashrate as the R9 cards would be classified properly as 200 series cards. With the updated driver, R9 280X cards would run much cooler and most could reach above 700KHash/sec.
After some tweaking, I have managed to get the PowerColor R9 280X to produce around 760KHash/sec per card. Let us look at how to configure the PowerColor R9 280X for higher hashrate and possibly lower power consumption.
How to optimize PowerColor R9 280X for Litecoin mining
Since the 280X is a rebranded 7970, it is possible to undervolt the cards using the VBE7 method that i have outlined in the previous tutorial: How to modify video BIOS to undervolt GPU in Linux. My PowerColor cards run completely stable at 1100mV, so if you are using my undervolting method, simply replace the 1081mV that i have recommended with 1100mV.
For this test, i am using BAMT version 1.1 with the latest AMD Catalyst drivers installed and CGMiner 3.7.2. You may learn more about setting up BAMT in my tutorial: Litecoin BAMT version 1.1 – Easy USB Linux mining distro.
I get the best result from this CGMiner configuration:
-g 2 -w 256 -I 13 --lookup-gap 2 --thread-concurrency 8192 --gpu-engine 1090 --gpu-memclock 1500
This configuration gets me around 760KHash/sec on each card with a low reject ratio. Most brands of R9 280X can reach hashrate of above 700KHash/sec. I will try to spend some time and post the configurations for each and every R9 280X i can get my hands on.