Has anyone ever downloaded an advert blocker and if so:

1 Is there one to recommend?
2 Does it slow down the computer?
3 Does it block all adverts?
4 Do they do what they say?

There seem to be lots of these blockers around but I've never dared download one as yet for fear of impairing computer performance on our 8yr old iMac.

I use Ad Block Plus, its a Chrome extension and I don't have any problems with my IMac performance

I can't see why you should think an Ad Blocker would have any impact on performance

I use Adblock Plus on my Mac. It's a Chrome extension. It works fine and has no effect on performance.

I'd say it actually makes it seem like there's been an improvement in performance because pages finish loading sooner.

I hadn't bothered with one until quite recently (on Fred's recommendation, actually) and now there's no way I'd be without it.

Many thanks to all of you.
With free downloads I 've always had a mixture of suspicion for something free, cynicism and ignorance of the technology!
Will take your advice.