As Ethereum Classic (ETC) is just about to hit DAG epoch 350 and Ethereum (ETH) about to follow it in a month or so later miners that are still using AMD Radeon GPUs with 4GB of video memory may start experiencing problems. So we are seeing some updated to mining software for Ethash addressing potential issues with the DAG size growing near the limit of the 4GB VRAM and trying to extend the usability of these video cards to the latest possible time. Miners with 4GB VRAM GPUS may already stared having issues with the main card if not using a built-in GPU due to the increased memory usage for the primary card by Windows, so the built-in Intel GPU for main card might help, alternatively switching to Linux operating system if you are currently running Windows may also help to gain a few more DAG epochs. You can also consider replacing the main video card with a one that has more video memory available in order to compensate for the increased VRAM usage cause by the Windows operating system.
The latest PhoenixMiner 5.0b update has added support for mining with 4GB AMD cards beyond the DAG epoch 350 (ETC is at #349 a the moment, ETH is a #338). Depending on the OS and driver versions you are using with this update you should be able to use 4GB AMD GPUs until epoch #372-#373 under Windows, and #380 under Linux. PhoenixMiner is fast (arguably the fastest) Ethash (ETH, ETC, Muiscoin, EXP, UBQ, etc.) miner that supports both AMD and Nvidia cards (including in mixed mining rigs). It runs under Windows x64 and Linux x64 and has a developer fee of just 0.65%. PhoenixMiner also supports Ubqhash for mining UBQ, ProgPOW for mining BCI, and dual mining Ethash/Ubqhash with Blake2s. According to the miner developers the speed of PhoenixMiner is generally faster than Claymore’s Ethereum miner in ETH only mode (about 0.4-1.3% speed improvement, though your results may be slightly lower or higher depending on the GPUs). To achieve highest possible speed on AMD cards it may be needed to manually adjust the GPU tune factor (a number from 8 to about 400, which can be changed interactively with the + and – keys while the miner is running). If you have used Claymore’s Dual Ethereum miner, you can switch to PhoenixMiner with minimal hassle as most of Claymore’s command-line options and configuration files are supported.
Some important tips for longest possible use of 4GB AMD cards with PhoenixMiner by the devs:
– If your rig is using Intel CPU, use the integrated graphics as primary display adapter. To do this, go to motherboard’s BIOS setup and change the “Primary display adapter” to iGPU (or integrated GPU). Also, if you are using actual monitor or HDMI plug, put it in the motherboard video output.
– If you can’t use integrated GPU, replace the primary GPU with one with 6GB or 8GB VRAM.
– Do not upgrade to a new AMD driver unless it is explicitly supported by PhoenixMiner. With 4GB AMD cards, this will not only lower your hashrate, but may also make it impossible to mine when the DAG epoch is above #350.
– After the DAG epoch moves past #350, the optimal
-gtvalue for the 4GB AMD cards may change, so try to run auto-tune again after DAG epoch #350 to find the best GT values for the cards.
What AMD drivers to use for mining under Windows:
– Good drivers: these are versions from 126.96.36.199 to 19.7.5 (inclusive), and from 19.12.2 to 20.4.2 (inclusive). These will allow you to mine until DAG epoch #372-#373 and won’t need restart of PhoenixMiner on each DAG epoch change.
– Not so good drivers: these are versions 18.1.1 to 18.10.1 (inclusive), and from 19.8.1 to 19.12.1 (inclusive). This will allow you to mine until DAG epoch #365-#366 and will require restart of PhoenixMiner on each DAG epoch change (for these drivers this will be preformed automatically unless you have added
-dagrestart 0command-line option to explicitly disable the auto-restart).
– Drivers older than 18.1.1 were not tested for 4GB DAG operation.
What AMD drivers to use for mining under Linux:
– Under Linux all relatively recent drivers (i.e. last 24-36 months) allow mining until epoch #378-#380, but there are much more driver bugs, so if you are happy with your current driver version, do not change it.