It won't stop the serious ones as they regularly spoof the IP address and change their names. I had one persistent set of pests spamming for an Indonesian kitchen manufacturer but I found a trick that stopped them with the Simple Machines forum software I run. It will perform word replacements on anything in the forum so I did multiple replacements on the word "kitchen" which was in the link they were posting which broke their link. In the replacements I tracked down a number of insults in Indonesian that referred to their intellect, masculinity and a number of other things so one smartie tried a url redirector as well so I just replaced it as well. They gave up after that.
I have been using the vbulletin plug in for stopforumspam for years on my vb forums and it works really well. It filters/stops a good bit of spam registrations. A few will still get through, but it's much easier to manage. You will occasionally get the odd real person trying to register from an IP address that is flagged in their database, but it's pretty rare.