AMD cpu slows down (I think)
trevor at haligonian.com
Sat Oct 30 16:18:47 UTC 2004
I'm trying to find info on my laptop problem but can't find anything really
explanatory. I assume it's something to do with CPU speed auto-setting on
battery power and your site seems to be relevant.
My situation: I have a Compaq Presario 2197CA, AMD Athlon XP-M 2800+ CPU. With
Fedora Core 1, no problems on AC or battery power. After upgrade to FC2 with
kernel-2.6.5-1.358, originally no problem (I don't recall). But at some point
I updated the kernel to kernel-2.6.8-1.521 and possibly then, possibly
because of some other "upgrade" my computer slips into a different mode when
on battery power.
In this "mode" it becomes extremely, irritatingly slow to use. A command shell
takes visible time to scroll/update. GUI windows take maddening seconds to
Research leads me to believe that this is a "feature" of the Powernowstuff or
something, but it is definitely not a feature I want.
A found a web site
(http://www.codemonkey.org.uk/projects/cpufreq/powernow-k7.shtml) that says:
"This meant that until version 2.6.6 of the kernel, Powernow was non
functional on these laptops."
"Compaq Presario 2100. Has 14 PST tables. None of which match the cpuid of
the processor (0x7A0)"
I conclude that this means that my original FC1 and FC2 kernels (pre-2.6.6)
would have had disfunctional support for Powernow but that my new kernel has
"fixed" support for this. And this, I assume, is the source of my problem.
However, I can find no docs about how to control Powernow or, better yet, turn
it off (I use my laptop at school and home and I rarely use battery power so
it's not an issue for me).
After my long ramble, 4 questions:
1. am I correct in my assessment of the situation, do you think?
2. how could anybody want to use a system that is struggling to update windows
and such, no matter how much longer it made their batteries last?
3. is my problem more likely the result of poor/nonexistent graphics
acceleration which causes the CPU to do graphics work as well as system work,
thus when the CPU is slowed down, graphics slow down?
4. how can I turn this damn Powernow thing off?
Thanks in advance.
Trevor Smith // trevor at haligonian.com
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