Radeon R9 280X Litecoin mining and Sweet Spot for 700KHash/sec (part 2)

Radeon R9 280X Litecoin mining and Sweet Spot for 700KHash/sec (part 2)

Radeon-R9-280X-Litecoin-mining-and-Sweet-Spot-for-700KHash-part-2

If you have read part 1 of this tutorial, you should have known that i promised to share my CGMiner configurations for both MSI Radeon R9 280X and PowerColor Radeon R9 280X.

 

You can check out the tutorial on How to build your own Litecoin mining rig with Radeon R9 280X if you are interested.

 

After much tweaking, I have managed to get both the MSI and PowerColor cards to produce around 700KHash/sec. At first, the MSI was giving me problem that it kept crashing when i tried to undervolt it. Solved the MSI problem by flashing it to the latest ROM and undervolt it thereafter. I am sure the hashrate can get a little higher, but at the moment, i’m happy with the GPU temperatures and low reject ratio.

 

How to optimize MSI & PowerColor R9 280X for Litecoin mining

I have slotted in a few cards to do the testing. When you are doing actual mining, it’s not recommended to slot in cards of different models, like in my example R9 280X and 7950, as R9 280X is more optimal at gpu-threads 2 while 7950 runs better at gpu-threads 1. There are ways around it though, like running two sets of configurations for CGMiner.

Radeon-R9-280X-Litecoin-mining-and-Sweet-Spot-for-700KHash-part-2-01

Undervolting

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. The MSI and PowerColor cards is completely stable at 1137mV and 1100mV respectively, so if you are using my undervolting method, simply replace the 1081mV that i have recommended for 7950 with the following:

  • MSI 1137mV
  • PowerColor 1100mV

Did i mention that i was having problem with undervolting the MSI card? You might need to flash the latest ROM on the MSI card before proceeding with undervolting. It is a fix released by MSI to address overheating and VRM temperatures. You can have a look at the tutorial here if you encounter the same problem.

 

CGMiner settings

These configurations plus undervolting results in very low temperature on the GPUs, and i expect the hashrate to go even higher with proper tweaking. But this should give you a good start with acceptable hashrate for the time being.

 

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.

 

-g 2 -w 256 -I 20 --lookup-gap 2 --thread-concurrency 22272 --gpu-engine 1108 --gpu-memclock 1800

-g 2 -w 256 -I 18 --lookup-gap 2 --thread-concurrency 22272 --gpu-engine 1045 --gpu-memclock 1725

 

This configuration gets me around 700KHash/sec on both the MSI and PowerColor card with a low reject ratio. I have read about others obtaining hashrate as high as 750KHash/sec on other brands and configurations, but with my limited testing, this is the result that i got without compromising stability.

 

Core clock speed of 1060MHz or 1080MHz are popular choices among R9 280X owners as a lot of people are getting good hashrates with that setting. You can always take the configuration as a base and tweak around to find the sweet spot for your card.

 

2/1 Update: Here is my updated CGMiner configuration for PowerColor card: Litecoin Mining – PowerColor Radeon R9 280X Sweet Spot for 760KHash/sec


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