This may sound dumb, but oh well...I just read where a Google research study on viruses indicated that about 1 in 10 web pages are equipped with malicious code, some of which have been passed on by download of 'third party widgets'. About 8,000 of these pages per month are appearing on the web and many already affected are legit sites. That got me to thinking... could a Mac accumulate enough of these to be affected speed-wise and response-wise, even though the virus could not penetrate the Mac like it would a Windows OS and actually highjack anything? In other words could virus code simply clog or hinder or slow down the Mac's performance?