Based upon these latest comments, I decided to re-install a clean copy of Yosemite GM (previous version was an upgrade.)
My new clean install is still getting over 200k interrupts on ASPIPlatform.
Code:
VECTOR CPU#0 CPU#1 CPU#2 CPU#3 CPU#4 CPU#5 CPU#6 CPU#7 TOTAL DEVNAME DRVNAME
42 0 0 0 0 0 0 0 0 0 IPIC
46 0 0 0 0 0 0 0 0 0 SMC com.apple.driver.AppleSMC
48 0 0 0 0 0 0 0 0 0 RTC com.apple.driver.AppleRTC
49 245413 0 0 0 0 0 0 0 245413 iMac12,2 com.apple.driver.AppleACPIPlatform
4b 0 0 0 0 0 0 0 0 0 HPET com.apple.driver.AppleHPET
4c 0 0 0 0 0 0 0 0 0 HPET com.apple.driver.AppleHPET