The fall months may be the season for colder weather and dying leaves, but in the software world it means major updates for security suites. We've reviewed and benchmarked 11 suites, organized them along the traditional line of cost, and picked one in each category that we highly recommend.

We looked at four updated free security options: AVG Anti-Virus Free 2011, Panda Cloud Antivirus 1.3, Microsoft Security Essentials 2, and Ad-Aware Free Internet Security 9. Other well-known free security programs, such as Avast and Avira, generally update in late winter or spring, so they were not included.

In addition to our product comparison charts (free | paid), check out CNET Labs' performance benchmark comparisons below. (Read more on how CNET Labs tests security programs.)

We can see from these tests that though no single program scored better than all the others, there were clear leaders in the key trials of start-up time impact, shutdown time impact, and time to complete a full scan. Panda Cloud Antivirus is highly competitive with AVG Free, whereas Norton's performance strengths lie in its threat prevention and detection, because several of its competitors leave a smaller footprint on your system.

Free security suite benchmarks: table.geekbox th{background-color:E6ECEF'text-align:left'font-weight:bold'} table.geekbox tr.even{background-color:CCCCCC'} .ratingGood{color:093'} .ratingAverage{color:666'} .ratingBad{color:C00'} Security program Boot time Shutdown time Scan time MS Office performance iTunes decoding Media multitasking Cinebench Unprotected system 42.5 11.28 n/a 917 180 780 4,795 AVG Anti-Virus Free 2011 55.24 11.59 548 1,039 200 870 4,709 Panda Cloud Antivirus Free 1.3 50.12 14.8 540 1,044 199 832 4,790 Microsoft Security Essentials 2 54 18 1,560 1,038 201 800 4,790 Ad-Aware Internet Security 9 54 18 1,620 1,039 199 797 4,792

*All tests measured in seconds, except for Cinebench. On the Cinebench test, the higher number is better.

Paid security suite benchmarks: table.geekbox th{background-color:E6ECEF'text-align:left'font-weight:bold'} table.geekbox tr.even{background-color:CCCCCC'} .ratingGood{color:093'} .ratingAverage{color:666'} .ratingBad{color:C00'} Security program Boot time Shutdown time Scan time MS Office performance iTunes decoding Media multitasking Cinebench Unprotected system 42.5 11.28 n/a 917 180 780 4,795 Kaspersky Internet Security 2011 47.49 17 1,750 1,068 207 823 4,661 Webroot Internet Security Complete 2011 47.86 15.97 1,459 992 198 848 4,729 BitDefender Total Security 2011 47.84 13.82 775 1,032 200 825 4,769 Trend Micro Titanium Maximum Security 2011 44.79 16.56 500 1,060 201 852 4,765 Norton Internet Security 2011 48.91 11.78 890 1,028 199 861 4,780 AVG Internet Security 2011 56.21 16.3 480 1,043 198 820 4,759 PC Tools Internet Security 2011 55 20 1,245 1,086 204 832 4,792

*All tests measured in seconds, except for Cinebench. On the Cinebench test, the higher number is better.