That's exactly what I do. And once I verify the best range to set for identifying a spammer for my servers (currently 20 seconds but that's partly server-specific: 2 of the forums are on one dedicated server while the other 2 are on a VPS with a different host - those on the VPS are slower so that's where the 17, 18, and 19 second spambots are showing up), then I just disable the emails.

I really think that this mod is the end for spammers

Sadly, I doubt it. Every time one new hole is plugged, the bastards find another one. And this does nothing about human spammers, of course - just spambots. But it certainly makes a huge difference.

another great mod was to send them a code by mail before registering and they had to enter that code to complete registration

Much Thanks. It's a shame refusal to comply with site policy made this necessary.

Thankyou kh99 for taking the time to recode this.
I will be installing it now and removing the other mods i was using.

Increased time to 25 seconds. Getting spambots trying at 21, 22, 23, 24 seconds. No actual humans blocked yet. Total today for 4 forums is 500+ attempts.

May have to go back to 30 seconds which is what I used before but didn't actually test myself.

I think there should be another anti spam integrated with this mod. something that will delay humans to register so that we can increase the time limit...

Yeah, can see where it's a problem if the bot time is approaching human time. The idea of delaying human registration would work, if I can figure out a way to do that. Or maybe one of the ideas that Lionel suggested would work to differentiate the bots from the humans.

Is it working with this mod?
I mean can I use it both in same time?
Anti-Spam Options - KeyCAPTCHA - Interactive CAPTCHA with Social Features