The OpenIV Package Installer is a miracle of reverse engineering. The fact that it can inject code into a 100GB encrypted archive at all is impressive. However, it is slow by nature.
Address Space Layout Randomization (ASLR) is a security feature that sometimes conflicts with OpenIV's memory allocation for large packages. Disabling it forces the OS to allocate memory linearly, speeding up file injection.
Below is a guide on how to troubleshoot and speed up the installation process.
When you install a .oiv package, OpenIV does not write directly to your mods folder. It extracts the contents to a first, then moves them. If your Windows Temp folder is located on a slow HDD (Hard Disk Drive) or, worse, a nearly full SSD, the extraction phase becomes a nightmare.
