Test setup: 2GHz AMD Sempron, 1GB, Win XP SP3, Comodo firewall 5.3.181415.1237, (builtin Realtek RTL8139/810x Family Fast Ethernet NIC)
Browsers: Firefox 4.0, Opera 11.01, Chrome 10.0.648.204
Webpages: Yahoo webmail, Fastmail webmail, Gmail webmail, and two large Google Docs files. This is a standard working set of webpages which I use.
Reference: With the previous "update" version of Avast(?), there were no occurrences of persistent 100% CPU usage.
1. I performed a standard Avast update, received version 6.0.1000, virus definitions 110328-0. During and following this update, CPU usage spiked to 80%-95% (avastsvc.exe) and never subsided.
2(a). After a forced powerdown, restart and chkdsk, CPU usage remained low. (b) After any browser with the above pages was started again, CPU usage pegged again. Avast UI was unresponsive, so could not disable protection.
3. Repeated all of (2) twice more.
4. Repeated (2a). After disabling WebShield, and starting a browser, CPU usage remained low.
It seems that the only way to avoid excessive CPU usage, in the case of browser access to AJAX-rich webpages, is to disable WebShield.
Any suggestions for other versions which address this? Or should I downgrade to fix this temporarily with WebShield enabled? Where can I DL the prior version?