Quote from: AVP on August 05, 2020, 10:58:38 PM

Have 4 RX470's with 4GB each. One of the cards is running only at 1.3Mh/s - does anyone know why this could be?

Using PhoenixMiner 5.0e, Windows 10, AMD drivers 18.6.1.

I'm tired already to write the same... Your drivers isn't in list of good drivers.
If to this card is monitor connected, you can't mine on it eth. Windows take some videomemory on 1st videocard to work.

Quote from: PhoenixMiner on July 23, 2020, 04:14:27 AM

Let us reprint the important message from the first post about the mining after DAG epoch 350:

IMPORTANT! All owners of AMD cards with 4 GB RAM must upgrade to PhoenixMiner 5.0e or later version to continue mining after DAG epoch 350 (both ETH and ETC has already passed DAG epoch 350). Additionally, here are some important tips for longest possible usage of 4 GB AMD cards with PhoenixMiner 5.0e and later:

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 6 or 8 GB VRAM.
Do not upgrade to a new AMD driver unless it is explicitly supported by PhoenixMiner. With 4 GB AMD cards, this will not only lower your hashrate but it will make impossible to mine when the DAG epoch is above 350.
After the DAG epoch becomes more than 350, the optimal -gt value for the 4 GB AMD cards may change. So, we recommend to run auto-tune again after DAG epoch 350 to find the best GT values for the cards.

After extensive testing of AMD Windows drivers for the last two years or so, we identified two broad groups of drivers:

Good drivers. These are versions from 18.12.1.1 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 0 command-line option to explicitly disable the auto-restart).
If you are using a pool with automatic switching between the coins (like nicehash for example), you should use one of the good drivers above, and shouldn't use the -dagrestart option.
Drivers older than 18.1.1 were not tested for 4 GB DAG operation. Specifically, there are multiple reports that the old blockchain drivers from 2017 doesn't work with 4 GB cards beyond epoch 350. If you are still using the blockchain drivers, you must upgrade to newer drivers if you have 4 GB AMD cards. After that, do not forget to turn on the Compute mode for all cards in AMD control center.

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.

Please note that the usage of 4 GB AMD cards on Windows 7 is problematic, because the blockchain driver from 2017 doesn't seem to work properly with big DAGs, and the newer drivers do not support turning on the compute mode. There are some possible workarounds with patched/hacked drivers but we haven't tested them and can't tell you how to do it.