Snow Leopard making my iMac turn on and off?

I had this issue,

I think its when you have wake on lan enabled.
Something like ATV spins up your disks to check its still in sync maybe?

 

Wake on network access is found in the Energy Saver pane in System Preferences. Unchecking that option may prevent your computer from waking up as it's doing - as I do believe it's enabled by default.

Attached picture shows the option (...I just had fun with Preview's Annotate option).

 

I don't want to thread-jack, and I'll probably make a post of my own after I'm done searching, but...

Anyone know of a way to keep WOL turned on but *not* have the computer intermittently wake up? I have a Mini as a media system in the bedroom and ever since it's been upgraded to SL, it wakes, clicks and whirs, then falls back asleep.

 

when i had leopard my iMac used to wake up a lot, but since Snow Leopard I ALWAYS have to shut it down now. it drives me mad. it can't stay asleep for more than 15 minutes. I've reset the PRAM and SMC and all that, reinstalled Snow Leopard, googled, checked surge protectors. god it drives me mad.

 

Apple Support Article

I didn't know why this happened until I found the article today..

http://support.apple.com/kb/HT3774

Half way down it says this.. check it out..

"Macs that have Wake on Demand enabled will occasionally wake for a brief time, without lighting the screen, in order to maintain registrations with the Bonjour Sleep Proxy. On some Macs, sounds from the optical drive, hard drive, or fans may be heard during these brief maintenance wakes."

So, if you want this feature on.. I.E, for ARD.. It looks like you'll have to deal..