This is a tested comparison of Anti-Virus software.

Performed May 2003 with latest products available.
Done as a joint effort by Network Associates, AV Comparison World and
PC Magazine.

It did not test firewalls.
It was tested against 500 windows executable virii,
100 unix/mac/beos virii,
50 SMTP virii,
40 SMTP trojans,
100 registry parasites,
10 keyloggers,
200 dangerous trojans.
(10,000 potential threats in total.)

It is compared on a 300MHz P2 system running WinXP Pro with 512Mb RAM.
* = Best of tested products if any.

 *A  |   N   |   M   |  *P   |  *K   |   F   |  N   |   P   |   S
  v  |   o   |   c   |   a   |   a   |   -   |  o   |   C   |   o
  a  |   r   |   A   |   n   |   s   |   P   |  r   |   -   |   p
  s  |   t   |   F   |   d   |   p   |   r   |  m   |   C   |   h
  t  |   o   |   e   |   a   |   e   |   o   |  a   |   i   |   o
     |   n   |   e   |       |   r   |   t   |  n   |   l   |   s
     |       |       |       |   s   |   e   |      |   l   |
     |       |       |       |   k   |   c   |      |   i   |
     |       |       |       |   y   |   t   |      |   n   |
=====|=======|=======|=======|=======|=======|======|=======|=======

Detectable claims-

Windows virii:
32k	30k	27k	32k	*58k	30k	27k	30k	26k

Macro virii:
500	450	300	500	500	400	100	300	0

Script virii:
30	30	30	50	50	40	20	30	10

Virii that effect other systems:
*8k	200	100	3k	5k	300	20	250	100

Trojans:
3k	100	150	2.5k	5k	3k	300	20	20

Parasites/spyware:
10	0	0	0	*22	0	0	0	0

E-Mail security is available-
Y	Y	Y	Y	Y	N	N	Y	N

How easy it is to use- (Hard Medium Easy)
Baed on a survey of 100 first time users.
M	M	H	E	H	E	E	M	E

Upgrading- (Hard Medium Easy)
E	M	M	E	E	H	H	E	H

System load- (Heavy Light)
H	H	H	H	L	L	L	H	L

Actual tested results are percentages of missed threats-

Manual Scan missed:
1%	13%	17%	1%	*.5%	4%	14%	14%	22%

On-Access missed:
2%	8%	20%	1%	*.6%	18%	25%	27%	28%

You can install the antivirus protection on all servers 
and workstations from one system.
Y	N	N	Y	Y	N	N	N	N

You can select what actions are to be taken upon viruses, 
such as disinfect, delete, move, or rename.
All yes. (Not many around these days that can not.)

You can choose to scan compressed files and nested email messages, 
and choose which file extensions to scan.
Y	Y	Y	Y	Y	N	N	Y	N

You can choose notification options for when a virus is discovered, 
such as notifying the administrator, the recipient, or the sender.
Y	N	N	N	Y	N	N	N	N

You can also choose heuristic scanning, which looks for new files 
that are similar to existing viruses.
N	Y	Y	Y	Y	N	N	Y	N

You can view a report of all recent virus activity, 
including the date and time and what action was taken.
Y	Y	Y	Y	Y	N	N	Y	N

Unknown viruses missed: (% of failed detection!)
0%	12%	12%	0%	0%	1%	2%	20%	10%

Documentation: (None Basic Complicated Full)
B	C	C	B	F	C	N	B	F

Easy to install:
Y	N	N	Y	N	Y	N	Y	Y

Easy to uninstall: (Y N Tragicly-no)
Y	T	N	Y	Y	Y	N	Y	Y

Time to scan: (Fast Medium Slow)
M	F	S	F	F	M	S	S	M


In this testing one might conclude:
Kaspersky is the most efficient but difficult to set up.
Avast and Panda run a close match with high performance but high demand.
McAfee and Norton take back seat and are bloated.
The rest do not scan as well, but usually have better speed and less demand.