Core temps always rise and fall much faster than socket or package temps. At least usually. Core temperatures can rise many degrees almost instantly, while socket temps generally have lower response times. It's normal. As long as your temps don't exceed spec, you're fine.
Aida is not the best method for thermal testing. Prime95 v26.6 and only v26.6, is.
Regardless of architecture. P95 v26.6 works equally well across all platforms. Steady-state is the key. How can anyone extrapolate accurate Core temperatures from workloads that fluctuate like a bad day on the Stock Market?
I'm aware of 5 utilities with steady-state workloads. In order of load level they are:
(1) P95 v26.6 - Small FFT's
(2) HeavyLoad - Stress CPU
(3) FurMark - CPU Burner
(4) Intel Processor Diagnostic Tool - CPU Load
(5) AIDA64 - Tools - System Stability Test - Stress CPU
AIDA64's Stress CPU fails to load any overcloked / ovevolted CPU to get anywhere near TDP, and is therefore useless, except for giving naive users a sense of false security because their temps are so low.
HeavyLoad is the closest alternative. Temps and watts are within 3% of Small FFT's.
Prime95 v26.6:
http://windows-downloads-center.blogspot.com/2011/04/prime95-266.html
And I'd use either HWinfo (NOT HWmonitor or open source monitor) or Core Temp to monitor temps:
http://www.hwinfo.com/download.php
http://www.alcpu.com/CoreTemp/