Occasionally minimize Virex so your computer spends less time displaying the results.
Open the Preference dialog and deselect the Show detailed results information checkbox. This preference is active by default to give you detailed scan information. However, because it displays scan results for every item scanned, it uses more system resources and takes longer to display.
Try scanning a smaller area of your computer, for example, select each folder rather than an entire volume.
Deselect some of the preferences in the Preference dialog.
Try scanning thoroughly less often. Scan your working areas most often, at least once a day.
Some viruses might not be detected if you choose the last option.
This information and more can be found at http://virexhelp.com/