Use software designed for real-time MIDI performances such as the freeware MIDI-OX to handle hardware to MIDI processing (see Resources). Routing your MIDI through 32-bit software designed for low latency real-time processing lowers the delay between striking a key on a MIDI instrument and triggering a software synthesizer.
Adjust your graphics card settings to reduce the background functions in your operating system. By reducing the bit-depth, color range and refresh rate of your graphics card you free your processor from numerous high-priority functions which cause delay in low priority functions such as MIDI processing. Alternatively selecting a graphics card with an internal processor accomplishes the same goal.
Use PCI or Serial Bus interfaces for your MIDI devices. PCI stands for Peripheral Component Interconnect and PCI devices plug directly into your motherboard via the PCI slot (see Resources). PCI and Serial Bus devices process more data and process that data faster than USB, or Universal Serial Bus devices. PCI MIDI interfaces are available at reasonable prices and demonstrate a significantly lower average latency than the more common and cheaper USB alternatives.
Use the most appropriate driver for your audio processing. Software drivers allow hardware such as MIDI devices to communicate with your PC and selecting the most up to date and most appropriate driver for your needs reduces latency. Using an ASIO driver allows you decrease the processing buffer to reduce MIDI latency although doing so may increase overall audio latency if your PC does not have the necessary processing power. MME drivers, though easier to use, generally results in increased latency as MME are Windows Designed audio drivers intended for general use and not real time audio recording.
Disable all unused MIDI devices on your PC or in your music editing software. Every time your software plays back or records audio and MIDI, the system must check every available port for incoming or existing data. Disabling unused MIDI and audio devices reduces the number of checks your software must perform during playback thus reclaiming processing time and increasing overall latency performance.