To Affi nity and Beyond
If you suspect that your dual-core CPU is
causing problems with a game or applica-
tion, and you want to quickly confi rm or
deny this, the best way is to manually set
the CPU affi nity for the application. Setting
affi nity essentially forces a process (applica-
tion) to temporarily use a specifi c CPU core.
To set the affi nity, start the application
or game that’s giving you problems. Press
Alt-Tab in order to jump to the desktop.
Press Ctrl-Alt-Del and select the Task
Manager. Click the tab labeled Processes
and locate the offending app or game.
Right-click it, scroll down and click “set
affi nity.” Remove the appropriate check-
marks so that only one CPU is selected for
the process. Click OK and close the task
manager. You can now press Alt-Tab to get
back into your game, which will now be
running on just one core.
Hide the Second Core
from Windows
If you’ve tried the aforementioned reme-
dies and are still having issues, and you’re
sure the problem is dual-core related, you
can always execute the fi nal fi x: ordering
Windows to stop using the second core
altogether. Obviously, nobody likes run-
ning a dual-core CPU in single-core mode,
but some apps simply will not run with a
second core, so this option might be your
only hope. And when the software manu-
facturer releases a fi x for the issue, you
can always undo this Windows fi x so the
second core is back in
business.
The fi x requires you
to tweak the Windows
System Confi guration
Utility, aka msconfi g.
Open it by clicking
Start, then Run, and
typing msconfi g. Click
the BOOT.INI tab and
click the Advanced
Options button.
Check the box labeled
/NUMPROC= and
set it to 1. Click OK,
reboot, and verify that
Windows is ignoring
the second processor
by right-clicking theTaskbar, and clicking Task Manager. Go
to the Performance tab, and under the
CPU Usage History, you should see just a
single CPU graph, not two.
In a month or seven, when the soft-
ware vendor has corrected the problem,
(or when you no longer need the app in
question), you can undo this tweak by
going back into the system confi guration
utility, selecting Advanced Options, and
unchecking the /NUMPROC= statement.
Reboot, go back into Task Manager, and
click the Performance tab. There should
now be more than one core visible.The quickest way to diagnose whether
a problem is dual-core related is to set
the application’s CPU affinity manually.If you’re experiencing major issues, you can configure
Windows to detect only one CPU core.Is It AMD’s
Fault?
If you search the Internet
for dual-core-related
gaming problems, you’ll
notice one thing imme-
diately: They all seem to
involve AMD’s Athlon 64
X2 CPUs.
But do they? AMD
offi cials fl atly deny
that it’s an Athlon-only
issue and point out that
Microsoft’s own hotfi x
applies to “dual-core”
processors, not just AMD
chips. That’s backed
up by some develop-
ers who have described
the problem occurring
on both Intel and AMD
dual-core processors. So
why does all the bitching
and moaning seem to be
coming strictly from the
AMD camp?
We suspect it’s
because of the populari-
ty of Athlon 64 machines
among gamers. In the
last two years, gamers
have fl ed from Intel to
AMD for two reasons:
better performance and
SLI dual-videocard com-
patibility (initially only
available on Athlon 64-
based motherboards).
Of course, some
dual-core users may
never experience any
problems at all. We
tried to replicate the
more common gaming
problems, using both
Intel and AMD dual-core
systems in the Lab, and
were unable to do so.
Several of our staffers,
however, have person-
ally had issues on their
dual-core machines at
home. The simple fact
is that, while elusive,
dual-core problems do
exist, and not only on
AMD machines.JUNE 2006 MA XIMUMPC 41