The FAT-32 file system is typically faster than the FAT file system. Start with the default compression ratio and increase it until you drop frames. Try three passes and take the best results of the three. After you've saved the captured image to another drive, run Scandisk on the standard setting to quickly defragment the drive. This line will prevent DOS from re-reading data after a write operation to make sure the correct data was written.
Verification slows down the writing operation.
Make sure the hard drive cache is turned on for the data drive. Refer to your SCSI card manual for more information. Heat buildup inside a system can wear down the system components and decrease capture performance. If your captured images look fine at first, but become jittery after the system has been capturing for a while, the capture card might be overheating. Some capture cards include a built-in audio card.