The latest ccminer 1.1.23 djm34 fork for the MTP algorithm used by ZCoin (XZC) seems to be providing the best performance for more recent Nvidia mining GPUs such as GTX 1070 or 1080 Ti including the latest RTX 2080 Ti as well (faster than the recently updated T-Rex miner). Owners of GTX 1080-based GPUs with GDDR5X memory can use the OhGodAnETHlargementPill to get a bit of extra boost in performance. The miner is open source, though there is a built-in 0.25% fee (that can be turned off) in the officially compiled binaries for both Linux and Windows. Do note however that the official windows binary requires CUDA 10.1-compatible video driver, so you may need to update your mining rigs. Linux binaries are available for CUDA 0.2, 10 and 10.1. Stability wise the miner may not be perfect yet, so make sure you have a loop set when running it to have it restarted if it crashes. NiceHash mining does not seem to be supported for the moment.