XMRStack has no arguments for graphics card overclocking, so any overclocking should be done with 3rd party software (MSI Afterburner) or native graphics card driver software. The miner does not use bat-file to run and relies on its own algorithms to optimize processors. The whole setup process is done in the miner itself.
List of some commands that can be applied to the miner additionally as needed:
--noCPU — disable mining on processors.
--noAMD --noNVIDIA — disable mining on graphics cards.
--openCLVendor NVIDIA --noNVIDIA — allows to use of OpenCL libraries for Nvidia graphics cards (in some cases, allows to get the higher hash rate on Nvidia graphics cards)