Most effective least memory demanding anti-virus?

[connchri]

Symantec emailed us about their latest release, We ran a BETA test for it in the office on the technician machines - as far as i could tell it was no better than it's ever been. I'd take your word for it though, since i haven't used the retail version i suppose i'm not really in a position to comment.

Although, in my mind - a bloatless antivirus that can be downloaded for free is more convenient than something you have to spend a tenner on and wait for it to be delivered.

You should try a demo then. I think you'd be pleasently surprised. The only reason I'm blowing the trumpet for them is because I certainly was. The last time I used Norton (sorry, had the displeasure of experiencing) was back in 2007 and, like most at the time, hated how it took over your PC, stuck tool bars left right and centre, dragged your machine to a crawl and generally was more hassle than it was worth. I read some decent reviews though, about the 2010 version, and decided to pay for Norton AV 2011 when I built my new rig a few weeks ago. And, just as the reviews said, it's far cleaner, leaner and quicker and I rarely notice it's even there.

In addition, it detected no fewer than 11 viruses on my external HDD that previously had never been found by MS security essentials or Avast. I can upload screen shots, if you wish, of my detection history. That hard drive was used with my old rig, and I ran Avast, AVG and MS Security Essentials over the course of my old rigs life.

It might cost £10 and a couple of days wait. But when I built a £1200 premium rig, it's worth it.

 

[thiefraccoon]

Norton has gotten much better.
but as far as your question goes, Nod32 by Eset is the answer.
If you're not looking to pay, I suggest AVG or MSE.

 

[clacker]

But it slows systems down to a crawl. Every single time i uninstall it the entire system speeds up, even if it is loaded with maleware. Not once have i not seen a dramatic speed increase from getting rid of one program.

I brought it from a shop when I got my laptop it's the newest version.

 

[Indigo]

Even the latest version of Norton is bloatware, which aggravates the hell out of me since Maximum PC has been recommending it lately. I want to smack them.

One of the best low memory usage AVs, for my own two cents, is Microsoft Security Essentials. Absolutely awesome, and very low resource usage. Stops things that I haven't been able to get Avira, Avast or AVG to stop.