Three Simple Steps to Goosing Your GPU
Using the free utility RivaTuner, you can push the speed of any AMD or Nvidia videocard that’s not currently
running at its full potentialWe chose RivaTuner over the overclock-
ing utilities that AMD and Nvidia provide
for one simple reason: This free third-party
program offers far greater user control. The
ability to permanently set a card’s fan speed,
the fl exibility to play with the GPU’s core
clock (either separate from or in sync with
its stream processors), and the capacity tocreate overclocking profi les for various com-
puting scenarios are just a few of the ways
RivaTuner stands out from other utilities.
To get started with your overclocking
adventures, download RivaTuner (version
2.06) from http://www.guru3d.com. Click Yes to
install available updates and accept the pro-
gram’s confi guration defaults. RivaTuner willcreate a registry database, which might take
a few minutes. Read the excellent readme
fi le while you wait, especially the FAQ.
Now you’re ready to begin. The steps for
overclocking an AMD GPU are slightly dif-
ferent than they are for overdriving an Nvidia
GPU, so proceed to the appropriate section
for further instructions.OVERCLOCKING AN AMD VIDEOCARD
SET FAN SPEED
In RivaTuner, click the Customize button
in the Target Adapter box and then click
the videocard icon to open a dialog box
labeled “Low-level system tweaks.” Click
the Fan tab and then place a check mark
next to “Enable low-level fan control.”
We want to see how far we can push the
GPU, so we need to keep it as cool as
possible. To do that, click Fixed. Now,
push the slider all the way to the right (to
100 percent) and click Apply.If the noise bothers you, set the fan
speed to a lower value (but realize that
you won’t be able to push your card as
far when using a lower fan speed). If you
can tolerate the fan at 100 percent, place
a check mark next to the box labeled
“Apply fan settings at Windows startup,”
place a check mark next to the box
labeled “Restore fan settings after sus-
pended mode,” and click OK.STEP 1
STEP (^2) ADJUST CORE CLOCK SPEED
Again, click the Customize button in the
Target Adapter box and then click the
videocard icon. Click the Overclocking
tab and then place a check mark in the
box labeled “Enable low-level hardware
overclocking.” Take the software’s advice
and reboot so that it can detect the
default memory and core clock speeds.
Relaunch RivaTuner after the system
restarts.
Click the Customize button again
and then the videocard icon to open the
“Low-level system tweaks” dialog box.
Place a check mark in the box labeled
“Enable low-level hardware overclock-
ing.” Now, use the Core Clock slider to
begin probing the limits of your GPU’s
core. If the core is stock-clocked, start
with gross adjustments—say, 25MHz at
a time (note: The arrow keys enable more
precision than the mouse).
Use a smaller increment if the card
is already overclocked or if your system
becomes unstable immediately. The idea is
to fi nd the system’s outer limit; once you’ve
done that, back down in 5MHz increments
until the system appears stable. Once you’ve
achieved that, place a check mark in the
box labeled “Apply overclocking at Windows
startup,” click Save, and then click the OK
button.
Before moving on to overclock the mem-
ory, stress-test the system with a benchmark
that can run unattended for at least one hour.
We use the two Shader Model 3.0 tests from
Futuremark’s 3DMark06 test suite because
they can be repeated up to 99 times. The
free version of 3DMark06 doesn’t run these
benchmarks, but two other widely used stress
tests are available for free: Nvidia’s GeoForms
(downloadable from http://tinyurl.com/ysxok4 )
and Masaki Kawase’s Rthdribl (downloadable
from http://tinyurl.com/c4d3q ).
OVERCLOCK
YOUR VIDEOCARD
OVERCLOCKING AN AMD VIDEOCARD
38 MAXIMUMPC | MAR 08 | http://www.maximumpc.com