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stqn

Member

Registered: 2010-03-19

Posts: 1,191

Website

Undervolting with phc 0.3.2 makes my system slower

Hi

I’m using the phc-intel AUR package to undervolt my Core i3 550. Theoretically it shouldn’t change my system’s speed at all, but I noticed that it does.

Firefox launch time:
- with undervolting: 11 seconds
- without undervolting: 5 seconds

Serious Sam 3 frames per second:
- with undervolting: 24
- without undervolting: 60 (capped by vsync)

The normal VIDs for my CPU are: 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
I have determined that my system is stable with the following VIDs, which I am normally using: 2 2 2 2 2 2 2 2 1 1 1 1 0 0 0 0
But I have also tried 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 which creates the same slowdown (for Firefox at least).

Actually after a few more tests, changing the first VID is enough to change the speed (I’m using the ondemand governor):
#            24 : 5.5 s
#            17 : 7 s
#            15 : 7 s
#            13 : 8 s
#            11 : 9 s
#             9 : 10 s
#             7 : 11 s
#             5 : 10 s
#             0 : 11 s

So… I don’t really have any question; I’ll just stop undervolting my CPU (and buy a new heatsink because the stock Intel one is now making too much noise). But maybe someone finds this interesting or has an explanation…

brebs

Member

Registered: 2007-04-03

Posts: 3,742

Re: Undervolting with phc 0.3.2 makes my system slower

Vids of 2 2 2 etc. are nonsense - far too low. Compare with my core2 duo:

Normal:  41 35 23 19
Lowest which are stable:  28 28 14 10