It all depends on what causes the high CPU usage. Assuming it is web-server related you should check the raw access logs. The access logs will show you what what pages users are loading and how frequently. If you see a lot of POST entries on the wp-login.php page, then my plugin can certainly help.
Try running a Quick Scan from the admin menu and give it at lease 90 seconds to see if it’s really stuck or just slow. If the Quick Scan doesn’t finish then try the Complete Scan from the Scan Setting page after changing the scan depth from -1 to 1, this should at least bring up the wp-login.php file and allow you to apply my brute-force patch.
Good luck, and let me know if you need any more help.