It is time to dust off those old AMD Radeon R9 290/290X and Radeon R9 390/390X GPUs you may have lying around and wondering what to do and make them mine Ethereum (ETH) with full power and some nice profit as well. The Hawaii and Grenada GPUs that these Radeon video cards use feature a 512-bit wide memory bus and that is more than welcome for mining Ethereum, even if they are already pretty old. You can be getting about 29-30 MHS hashrate for mining Ethereum (ETH) with these, although they are more power hungry than more recent GPUs that offer the same performance it is still worth it with with high mining profit we have at the moment.
With Radeon R9 290/390 GPUs there is a bit of a catch in order to get 29-30 MHS Ethash mining hashrate with about 150-200W of power usage per video card (with optimized video BIOS for lower power usage). It is only possible to do it under Linux as the AMD video drivers for Windows 10 do not feature support for Compute Mode for Hawaii GPUs and you can get only 14-15 MHS, but the Linux drivers do and you get 29-30 MHS. What you need to do is to make sure you have up to date video drivers and that you are using the latest version of PhoenixMiner in order to be able to fully utilize the Radeon R9 290/390 GPUs for mining Ethereum (ETH).
If you are not very good with Linux you can make your life much easier with a dedicated crypto mining operating system such as HiveOS. HiveOS simplifies getting a mining rig with AMD Radeon R9 290/390 GPUs ready for mining Ethereum (ETH) with the full 29+ MHS hashrate. Again, in order to be able to get the optimal mining performance for Ethereum on these Hawaii GPUs you need to stick to Linux, Windows is not an option for the full performance and HiveOS just makes it easy. Do note that for HiveOS you can use the promo code CMB10USDPROMO that will give you $10 USD in your account balance!