This morning, I noticed the system temperature was oddly low, only just above 40C. I didnt mind at first, but then I felt it seemed to run slower than before, which might just from confusion after I checked the frequencies from /proc/cpuinfo.
I had not looked at file for years, and I saw the frequency was fixed at 1833MHz and 1000MHz, two cores, respectively. So, I tried the ultimate fix, turning it off and on again, didnt work. I began to wonder if anything got updated recently, not the kernel nor any system/hardware stuff that I could remember.
At this point, I laughed before I knew there must be a setting wrong and for years, I had not realized that. So I went back to the power management in kernel configuration and found that I might have been using the wrong governor since 2012-08-27 as kernel 3.4 recommended ondemand governor according to ArchWiki.
That was 3.5 years ago.