Fast, free malware scanner

Of late, I've used both Ad-Aware and Spybot S&D free versions and both seem to be taking a lot longer than before--45 to 60 minutes for the simple scan compared to the 15-20 minutes. I suppose there are more threats out there, but ....If this is too long, are there other good, free and faster scanners available? Do I really need an after-the-fact scanner with the ccleaner, Spyware Blaster and Avast Free that I'm using? Thanks.

 

Thank you very much for that link. Very informative and helpful.

 

New BETA versioon of Spybot released recently.

SpyBot-Search & Destroy Tools Beta 1.6.0.25
http://www.majorgeeks.com/download5396.html

I'm using it but haven't noticed a 5x improvement in scanning speed. Less than that, but faster than previous.

Bazza