[Tfug] Got an odd one: laptop AMD CPU stuck at 800mhz, won't jump to 1, 600

[Jim March]

Turned out to be a Dell-specific issue whereby the damnthing didn't
like the power brick for some reason and throttled back in response.

To be specific, I did this command at the terminal:

    gksudo gedit /etc/default/grub

Took the line that said:

    GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

...and turned it into:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash processor.ignore_ppc=1"

...saved that, and at the terminal did:

    sudo update-grub

Fixed it like a champ. It now defaults to 1.6gHz speed BUT I can still
manually set it to speed-shift on demand, or lock it into "low gear"
if I want.  Other solutions both didn't work AND would have locked it
into high gear if they did (overriding or disabling CPU frequency
shifting).

Sidenote...an interesting speed comparison between my previous lappy
(Intel Pentium Dual-Core T2370 (1.73gHz) with a i965/X3100 and the new
critter, an AMD Turion X2 TL-50 (1.6gHz) with an old ATI Radeon X1270
video card. The Intel-based critter felt just fractionally faster.
Difference isn't huge but in things like flash playback, it was
definitely quicker. But you'd have to really pay attention...both are
usable to a very similar degree.  The X1270 is supposed to be a bit
faster than the i965, while the TL-50 is rated a bit slower than the
Intel CPU.  The result is nearly a wash.

One other nice thing about the AMD chip: unlike the "Pentium
Dual-Core" it has hardware virtualization support.  I haven't done
performance testing with Virtualbox yet but regardless of speed, this
means I'm no longer stuck with VirtualBox as my sole choice for
virtualizing my copy of XP - I can run other choices now!  So that's
cool.

Both have 2gigs RAM.

BUT!  This is looking at 2D.  3D is blowing chunks - "compiz
--replace" doesn't work at all, and even GLXGEARS fails with the 1270.
 Something is FUBAR here...I'm researching that now, and am not yet
done "googling it" :).

The replacement AMD/ATI machine is clearly Dell's old "business
series" critter (Latitude) and the build quality on the chassis is
just night-and-day different (better!). So it's worth swapping over,
for me...after four years of daily carry my old one (Inspiron 1525)
was visibly falling apart :(.

Big thanks to Kdesu on the reddit /r/linux forums:

http://www.reddit.com/r/linux/comments/oqgu8/got_an_odd_one_laptop_amd_cpu_stuck_at_800mhz/c3jby3b

...for the tip that worked.

Jim