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Which AntiVirus is the Lightest memory usage

Few days ago I got an email from one of my friend asking me which would be the best free antivirus program to use on an old pc which won’t slow down the computer. There are easily 10 types of free antivirus and I couldn’t really tell which one is the lightest on memory usage because I’ve never really compared all of them. I know for sure the latest AVG FREE 8.0 is bloated and it takes up a lot of memory and I could only guess “maybe” Avira Antivir Personal is the lightest. Let’s not guess and put those antivirus to the memory test. Actually this question has been on my mind for quite some time now and I’d be glad to know the answer.

Today I found 27 types of antivirus programs for their memory usage from website that can be trusted.The website put the list of anti-virus which have loghtest memory usage. So check it out, I am sure you’ll be surprised by the results!

Here is the list of anti-virus that are arranged from the lowest memory usage while idle to the most memory usage.


1. PC Tools AntiVirus Free Edition 4.0.0.26 (freeware) pctools antivirus

Total memory usage during idle: 5680K
Total memory usage during scanning: 23948K
Cannot detect private trojan
Link: http://www.pctools.com/free-antivirus/

2. Kaspersky Antivirus 2009 v8.0.0.357 (shareware) Kaspersky

Total memory usage during idle: 6565K
Total memory usage during scanning: 50892K
Detects private trojan through heuristic method, not through virus definition
Link: http://www.kaspersky.com/kaspersky_anti-virus

3. Spyware Terminator v2.2.3.444 (freeware) Spyware Terminator

Total memory usage during idle: 7624K
Total memory usage during scanning: 64292K
Unable to detect virus with the built-in antivirus. However when tried to run the trojan, HIPS picks it up as a threat
Uses ClamAV for antivirus protection
Link: http://www.spywareterminator.com/

4. Norton AntiVirus 2008 (shareware) Norton Antivirus

Total memory usage during idle: 8424K
Total memory usage during scanning: 78008K
Cannot detect private trojan
Link: http://www.symantec.com/norton/antivirus

5. BitDefender 10 Free Edition (freeware) Bitdefender

Total memory usage during idle: 9668K
Total memory usage during scanning: 42492K
Cannot detect private trojan
Link: http://download.bitdefender.com/windows/desktop/free/final/en/bitdefender_free_v10.exe

6. Avira AntiVir Personal 8 (freeware) Avira

Total memory usage during idle: 10072K
Total memory usage during scanning: 70072K
Detects private trojan through heuristic method, not through virus definition
Link: http://www.free-av.com/

7. Kaspersky Internet Security 2009 v8.0.0.3578 (shareware) KIS 2009

Total memory usage during idle: 16180K
Total memory usage during scanning: 44216K
Detects private trojan through heuristic method, not through virus definition
Link: http://www.kaspersky.com/kaspersky_internet_security

8. Rising Antivirus 20.44 (freeware) Rising Antivirus

Total memory usage during idle: 16252K
Total memory usage during scanning: 59704K
Cannot detect private trojan through virus definition but blocks it from executing
Link: http://www.freerav.com/

9. DriveSentry 3.1 (freeware) Drivesentry

Total memory usage during idle: 16992K
Total memory usage during scanning: 18504K
Cannot detect private trojan
Link: http://www.drivesentry.com/

10. avast! 4 Home Edition (freeware) Avast Home Edition

Total memory usage during idle: 23100K
Total memory usage during scanning: 63416K
Cannot detect private trojan
Link: http://www.avast.com/eng/avast_4_home.html

11. CA Anti-Virus 2008 (shareware) CA Antivirus

Total memory usage during idle: 37756K
Total memory usage during scanning: 47556K
Cannot detect private trojan
Link: http://shop.ca.com/virus/antivirus.aspx

12. AVG Anti-Virus Free Edition 8.0.138 (freeware) AVG

Total memory usage during idle: 38244K
Total memory usage during scanning: 88244K
Detects private trojan through virus definition. Maybe they got a sample of the private trojan and added the detection to its virus definition
Link: http://free.avg.com/

13. ESET NOD32 Antivirus 3.0.669 (shareware) eset nod32

Total memory usage during idle: 40364K
Total memory usage during scanning: 46012K
Cannot detect private trojan
Link: http://www.eset.com/products/nod32.php

14. ESET Smart Security 3.0.669 (shareware) eset smart security

Total memory usage during idle: 42640K
Total memory usage during scanning: 39284K
Cannot detect private trojan
Link: http://www.eset.com/smartsecurity/

15. Trend Micro AntiVirus plus AntiSpyware 2008 (shareware) Trend Micro

Total memory usage during idle: 42608K
Total memory usage during scanning: 63704K
Able to detect private trojan as suspicious activity and blocked it from executing
Link: http://apac.trendmicro.com/apac/products/personal/antivirus-plus-anti-spyware/

16. ZoneAlarm Antivirus 7.0.483 (shareware) Zonealarm antivirus

Total memory usage during idle: 52772K
Total memory usage during scanning: 97200K
Cannot detect private trojan
Link: http://www.zonealarm.com/store/content/catalog/products/zonealarm_antivirus.jsp

17. BitDefender Antivirus 2008 v11 (shareware) Bitdefender

Total memory usage during idle: 56440K
Total memory usage during scanning: 73720K
Able to detect private trojan as threat
The free version uses BitDefender v10 and the shareware version uses the latest v11. So I had to make a comparison on both BitDefender products.
Link: http://www.bitdefender.com/PRODUCT-2194-en–BitDefender-Antivirus-2008.html

18. Comodo AntiVirus 2.0.17.58 (freeware) Comodo antivirus

Total memory usage during idle: 56668K
Total memory usage during scanning: 76668K
Unable to detect virus through its virus definition. However when tried to run the trojan, HIPS picks it up as a threat.
Link: http://antivirus.comodo.com/

19. F-Secure Anti-Virus 2008 (shareware) F-Secure

Total memory usage during idle: 61972K
Total memory usage during scanning: 178824K
Cannot detect private trojan
Link: http://www.f-secure.com/home_user/products_a-z/fsav2008.html

20. Moon Secure Antivirus 2.2.2.163 (freeware) Moon Secure Antivirus

Total memory usage during idle: 71528K
Total memory usage during scanning: 71528K
Cannot detect private trojan
No changes in memory usage during idle and scanning
Uses Clam Antivirus engine and definition
Link: http://www.moonsecure.com/

21. Panda Antivirus 2008 (shareware) Panda Antivirus 2008

Total memory usage during idle: 76344K
Total memory usage during scanning: 101416K
Cannot detect private trojan
Link: http://www.pandasecurity.com/malaysia/homeusers/solutions/antivirus/

22. McAfee VirusScan Plus 2008 (shareware) Mcafee VirusScan plus

Total memory usage during idle: 87632K
Total memory usage during scanning: 140484K
Detects private trojan as backdoor program
Link: http://us.mcafee.com/root/package.asp?pkgid=276

23. Norman Antivirus & Antispyware (shareware) norman security suite

Total memory usage during idle: 99856K
Total memory usage during scanning: 201660K
Cannot detect private trojan
Link: http://www.norman.com/Product/Home_Home_office/NVC/49922/

24. Windows One LiveCare 2.5 (shareware) Windows One LiveCare

Total memory usage during idle: 102868K
Total memory usage during scanning: 107868K
Cannot detect private trojan
Link: http://onecare.live.com/site/en-us/default.htm

25. eEye Blink 4.04 Personal Edition (shareware) eEye Blink

Total memory usage during idle: 117972K
Total memory usage during scanning: 131412K
Cannot detect private trojan
Free 1 year license for US/Canada residents
Link: http://www.blinkfree.com/

26. G DATA AntiVirus 2008 (shareware) G-data antivirus

Total memory usage during idle: 130544K
Total memory usage during scanning: 175176K
Cannot detect private trojan
Link: http://www.gdata.de/trade/US/productview/819/16/

27. Quick Heal AntiVirus Plus 2008 v9.50 (shareware) quickheal antivirus

Total memory usage during idle: 151660K
Total memory usage during scanning: 201660K
Cannot detect private trojan
Link: http://www.quickheal.co.in/small-desktop-edition-win.asp

There you have it. Now you know which antivirus to recommend to your friend if they ask you which one doesn’t slow the computer down. For me, I think that the best for shareware would be Kaspersky Antivirus 2009 and as for freeware, Avira Antivir. Both is light on memory usage and has very good heuristic detection to detect unknown threats that is not on the virus definition. As for NOD32, it takes up 40MB memory usage on idle and 46MB during scanning. Even the latest major update version 3 couldn’t detect the private trojan.

Just choose which one is more comfortable to your computer. =)