From the Release Notes:
Using GVI and the VSL Performance Tool
1. Download the Maple MIDI Router – Free from http://www.marblesound.com
2. Open GVI as a plug-in in your host DAW
3. Set the Performance Tool input to “physical in” and output to Maple MIDI router
4. Set the DAW track's input to the Maple virtual MIDI cable and its output to GVI
New Feature in 3.53
Windows XP 64
GVI has been tested on Windows XP 64 systems and found to be compatible.
Maintenance Items in 3.53
• The cause of rare cases of GVI instability on dual core systems at high polyphonies has been fixed in 3.53.
• Previously, GVI could become unstable if switching GigaPulse encoded instrument presets while audio was being played. This has been fixed in 3.53.
• Patch changes in Steinberg hosts are now reflected in the GVI UI.
• In GVI 3.52 the Unload All and Unload Unused functions in the Loaded Instruments Viewer did not work. This has been fixed in 3.53.