Miners using AMD Radeon RX 4xx/5xx GPUs to mine Windows ETC in the near future may start to get weirdly poor performance on the first video card in Riga, while the rest of the GPUs will work as usual. The reason for this is quite simple, although we are still quite far from 4 GB of DAG file size, since in the current 337 ETC era a DAG file of 3.63 GB in size is required (for the miner from Claymore), the first GPU in the system uses more video memory, since it needs display the operating system interface. As a result, when using Windows, the first GPU consumes approximately 140-150 MB of additional video memory. Therefore, the actually used memory is approaching the maximum size of 4GB. As a result, instead of 20-30 MH/s, you can start receiving 1-2 MH/s for the first video card in the system, and soon it may even stop showing any hashrate at all.