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BASICS
All modern graphics cards have a Graphics Processing Unit (GPU) chip
which performs graphics calculations, and memory which the GPU uses to
perform these calculations. Each of these has a default clockspeed
determined by the manufacturer. The performance of a graphics card can be
boosted by increasing the clockspeeds beyond the manufacturer's default
settings. This is what we call overclocking.
What is the Core clock?
The core clock is the clockspeed at which your GPU (also known
as graphics chip) operates. It is measured in MHz, just like a CPU.
What is the Memory Clock?
The memory clock is the clockspeed at which your graphics
card's memory operates. It is also measured in MHz. All modern graphics
cards use DDR (double data rate) memory, which explains why some people
may refer to the same memory speed as 350MHz or 700MHz. 700MHz is the DDR
clock speed while 350MHz is the actual clock speed. The DDR clock speed is
always twice the actual clock speed. Please do not confuse this. It is
quite easy to figure out if the memory is being referred to in actual
clockspeed or DDR clockspeed. The fastest actual graphics memory speed
today is around 500MHz (meaning 1000MHz DDR). So you know that anything
above 500MHz must mean DDR speed. Also, most memory these days operates at
an actual speed of around 300+MHz (600+MHz DDR). Any memory above 300MHz
in actual clockspeeds is usually only used in mid-range or high-end
graphics cards. So if you see, say, 400MHz on the specification sheet of a
low-end graphics card (for example a Radeon 9600SE), it means that it
operates at 200MHz actual speed.
When someone refers to the clockspeeds as 380/680, this means that
380 is the core clock and 680 (DDR) is the memory clock.
Overclocking Software - RivaTuner v2.0
For this guide I will be using RivaTuner v2.0 RC14.3 (The
latest version as of the writing of this article).
Download it HERE.
RivaTuner is easy to use and supports both ATi and Nvidia cards.
Newbie Warning: Please do not mess
with the advanced settings in RivaTuner as it may cause problems for you.
Only adjust the settings that I will go through in a moment.
After installing RivaTuner, run the program. You will see a screen like
below. Do not worry about the color differences compared to what you see
on screen. The image below was highly compressed so that those with
dial-up will not have to wait forever for the picture to open.
Click on thumbnail to view full picture
Using RivaTuner for overclocking:
- At the main screen, click on the little arrow to the right of the
word "Customize...". A little menu with 6 icons in a row
will pop up like in the picture above.
- Click on the 1st icon which is labeled "Low-level system
settings". A new screen will pop up like in the picture below.
Note that the default clock settings on your graphics card may differ
from mine as I am using an ATI Radeon 9800 Pro.
Click on thumbnail to view full picture
- Click on the checkbox at the top that is labeled "Enable
low-level hardware overclocking".
- A message will pop up asking if you want to detect the clock
frequencies now or reboot before detecting. I recommend that you select
the reboot option.
- After rebooting, run RivaTuner again. Notice that you can now move
the Core clock and Memory clock sliders.
Wait! do not move them just yet! On next page where I will show you what
to do.
- Make sure that the "Apply overclocking at Windows startup"
box is UNTICKED! You will only want to tick this AFTER you have found
the maximum stable overclock!
Next Page - Stability Testing
and Overclocking
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