IMatch by default utilizes all available processors and disks when indexing files. It automatically adapts to your system configuration to balance and to overlap file system operations and in-memory computations for optimal performance.
Sometimes, if you plan to add large batches of files from slow media like CD-ROM or DVD, you can achieve a better performance by telling IMatch to use only one processing thread and not several in parallel. What gains a lot of performance for hard disks and fast network storage can actually be much slower for slow media like DVD or CD-ROM.
To change how many parallel processes IMatch uses to index files, go to Edit > Preferences > Application: Process Control. To limit both reading and writing to one parallel process, set both values to 1 (one).
After you have indexed your CD-ROM and DVD collection, revert both values back to the default value of 0 (zero) for optimal performance when indexing files on hard disks and similar storage media. 0 means: Automatically adapt to the available number of processors and overall system performance.
If you manage files on network storage, you can also change these values to try out which values give the fastest throughput. The best value cannot be determined automatically, it all depends on your network connection speed and the server or NAS system you are connecting to.
Adjusting the process control values is not required if you just want to add a few hundred files. But if you plan to index 10,000 or even 100,000 files, you can skim off a few hours by testing which values work best.
On some configurations, the defaults selected by IMatch may not work best. This is sometimes the case for NAS devices in combination with slow networks (Wi-Fi!) or on some notebooks which reduce CPU speed to compensate for additional heat caused by prolonged disk activity (e.g. while writing back hundreds of files). If you experience this, you can limit the number of parallel write-back threads to 2, to see if this improves overall throughput.
The Info & Activity Panel and the Progress Overlay show you how IMatch is performing and you can use these elements to judge which settings work best for your system and environment.