For the Clam Sentinel real-time scan, the system monitor looks at files that have one
of the extensions that are most often used by malware. If the file is okay, then Clam
Sentinel does a scan of the file with ClamWin looking at about 120 file extensions.
That is a lot of extensions, and it takes some time to scan a file to see if it has one
of the 120 extensions. I think that you can reduce the number of extensions that are
scanned during the ClamWin scan and still have good security. I use the following 40
extensions:
asp, aspx, bat, chm, cmd, com, cpl, dll, doc, docx, drv, exe, hlp, htm, html, inf, js,
lnk, msi, ocx, pdf, pif, ppt, pptx, rar, reg, rtf, scr, swf, tmp, url, vbs, xls, xlsx,
zip, cab, class, hta, jar, and sys.

You can change the extensions to scan in Clam
Sentinel's Advanced Settings. If you decide to revert back to the original 120
extensions later, you will have to uninstall Clam Sentinel and then re-install it.
For extra protection, you should use ClamWin and Clam Sentinel along with another
antivirus program. If you get a malware on your computer that Clam Sentinel does not
detect, there is a good chance that the other antivirus will detect it.

For the other antivirus, use whatever you want, but I recommend Microsoft Windows Defender for
Windows 8 computers and Microsoft Security Essentials for older computers. Both are
free--like Clam Sentinel/ClamWin. Windows 8 computers have Windows Defender built in. New computers usually have a trial version of something else that will expire in 30 days or so. If you uninstall this trial version, Windows 8 computers will revert back to the Windows Defender
antivirus. In my opinion, you will have less problems using ClamWin/Clam Sentinel with
Microsoft's antivirus.

Regardless of what other antivirus you use, whitelist/exclude the ClamWin clamtmp
extension (if this is possible) the ClamWin quarantine and signature folders, and every
.exe file in the Clam Sentinel and ClamWin program folders from the other AV's scans.
This will prevent excess system use and conflicts between antivirus programs.

Set ClamWin and the other antivirus for automatic updates, and stay safe!

Regards,