Hi, I was using v0.15 with two GTX 1080 TI and then tried to switch to v0.20 and v0.21. I played with the batch a little but I never got more than 80% of the hashrate of the v0.15. Hope this gets better (again). Good work so far

v0.15 never existed

Can you show us your current batch for starting 0.21? Lets have a look if I see something that vould cause problems. Also you coult try running it without batch the old 0.1x way with just one card per miner instance. Lets hunt that issue

v0.13, my bad.
this is my current batch, I've tried "WORKB" with 1,2,3,4,5,8,12, all max -20% of v0.13. Also tried using the v0.21 for one card, same result. This batch is from the last test on one card:
Rem Insert your pool name here
set "POOL=mnx.suprnova.cc"
Rem Insert your pool port here
set "PORT=7077"
Rem Insert your user and worker names here
set "USER=xxxxx"
Rem Insert your worker password here
set "PASS=xxxxxx"
Rem Insert the index of the platform you want to run on. Run lolMiner-mnx.exe --list-devices
Rem to see all available platforms and the available devices for each platform
set "PLATFORM=1"
Rem Insert your devices to run the miner here. For multiple GPU pass a comma separated list, e.g.: 0,1 for using two GPUs
set "DEVICE=0"
Rem Set the work-batch-size (see readme file)
set "WORKB=3"
The batch for the v0.13 is this:
lolMiner-mnx.exe --server mnx.suprnova.cc --port 7077 --user xxxxx -- pass xxxxx --platform 1 --enable-nv-hotfix
works fine on 18khash per card apart from the occasional shutdowns of the miner.
edit: I don't think it is related, but my onboard graphics (intel) is platform 0 and is used as primary. MB is 110 Pro BTC+