|
|
|
Overclocking Your 3D Accelerator
David Yee, 10 August 1998
|
| In trying to squeeze every single bit of
gaming performance out of your PC, you might want to consider overclocking your 3D
accelerator. There are certainly limitations to how much you can overclock your
video card's memory clock, but they vary according to the chipset and the type of RAM on
board. I've tried overclocking on several popular cards (sorry I couldn't try them
all). Specifically I tried the ATI Xpert 98 AGP
(8 Mbyte RagePro 2X), Creative Labs 3D Blaster
Voodoo 2 (12 Mbyte 3Dfx Voodoo 2), Eontronics Picasso 740 AGP (8 Mbyte Intel i740), STB Velocity
128 PCI (4 Mbyte NVIDIA Riva 128), and the Hercules Thriller 3D (8 Mbyte Rendition Verite V2200). Unfortunately the i740
card did not allow for overclocking, but the other boards were able to do it. I will
be doing the same experiment with a Millennium G200 card, but that will be included in its
upcoming review. Because overclocking your video card requires you to have adequate
cooling, at the bottom of the page I've
listed some tips for getting rid of the heat.
The system configuration is as follows: Pentium II 300, Asus P2B, 96 Mbyte PC 100 SDRAM,
Diamond Fireport 40, and Quantum Viking 4.5 NSE Ultra Narrow SCSI Hard Drive.
Windows 95, DirectX 5, Forsaken 1.0 (640x480), Quake II 3.17(640x480), and Incoming
Lux-et-Robur (640x480) were used. All video cards had V Sync disabled when the option was
available. Where specified, TennMax's Stealth
V2 Cooler and the Lasagna Cooler were used. PowerStrip 2.24E by EnTech was used to perform the overclocking. [update]
I received quite a number of emails asking me exactly how to overclock, so here're the
detailed instructions. 1)Download and install PowerStrip. 2)Run
PowerStrip. Right click on the first button. 3)Go
to Advanced options. 4)Select About the PowerStrip.
Now click on the Performance tab. Now you should see a slider to
adjust the Memory clock. Pick your setting, hit Apply, then confirm the change, and
you're set! |
|
ATI
Xpert 98 |
| Powered by the RagePro 2X chip, the Xpert 98 proved to be the most
overclockable of the bunch. Without any additional cooling, the card was fully
functional even at the maximum of 120 MHz. Despite this, Quake 2 performance did not
increase very much as memory clock was raised above the default 100 MHz. At 125 MHz,
I was only able to get 24.4 FPS, a 0.4 FPS increase from the default. Forsaken
performance scaled much better, however, and there was a 9.25% increase in framerate at
120 MHz over 100 MHz. Overclocking your RagePro board is an excellent way to boost
the speed of your Direct3D games. Drivers used: version 5.2, OpenGL beta 3 |
| |
 |
 |
| |
Summary |
| Overclocked stability |
Excellent- stable up to the maximum of 120 MHz |
| Should you overclock? |
Yes |
| Recommended memory clock: |
110 MHz, higher if you have good cooling. |
| Default / Max allowable memory clock: |
100 MHz, 120 MHz |
| |
|
Creative
Labs 3D Blaster Voodoo 2 |
| The Voodoo 2 board is already such a terrific performer that you might wonder
why you would ever want to overclock it. After testing, I thought the same thing
too. I found that you can overclock the card to 99 MHz without additional cooling,
but going above that is very difficult. With the help of TennMax's excellent Stealth
V2 Cooler, I was able to run the Quake II tests without crashing at 100 MHz, but 101 MHz
did not work. I suspect that it is not the heat that is preventing overclocking
beyond 100 MHz because the chips did not feel extremely hot, but rather the quality of the
memory was the culprit. Even at 100 MHz, however, there was only a 2.3% increase in
Quake II performance- hardly worth the increased instability. I used Incoming
instead of Forsaken so that the refresh rate is not an issue, so you can say that the
Direct3D results cannot be compared with the other cards. But regardless Incoming
did not scale very well to say the least. At 99 MHz, the maximum stable clock rate,
the card was only 0.22% faster than 90 MHz. Again I would like to stress that since
the Voodoo 2 card is already extremely fast, there's no need to overclock this baby.
Drivers used: 3Dfx's drivers version 1.03.01 |
| |
 |
 |
| |
Summary |
| Overclocked stability |
Not very good- you should probably not go above 96 MHz |
| Should you overclock? |
No- unless you have awesome cooling and/or a special cooler for the board (e.g.
the Stealth V2 Cooler) |
| Recommended memory clock: |
The default setting for your Voodoo 2 card (90 to 95 MHz) |
| Default / Max allowable memory clock: |
90 MHz, 105 MHz |
| |
|
Hercules
Thriller 3D |
| The Rendition Verite V2200 card is fairly overclockable. The chipset
clock speed is set to 1/2 of the memory clock speed. Since the default memory speed
was 125 MHz, the RISC chip was running at 63 MHz. I was able to drive the Thriller
up to 67/134 MHz without any problems, but beyond that lock-ups became frequent.
With TennMax's Lasagna Cooler, I was able to finish the Quake II tests at 69/138 MHz, but
Forsaken still locked up. It is somewhat unusual to see how Quake II performance
scaled much better than Forsaken. At 67/134 MHz there was a 10% increase in Quake II
framerate while in Forsaken there was only a 1.5% increase. This likely means that
the OpenGL drivers are more optimized than the Direct3D drivers. By the way, this
was the only card that had enough room to attach the TennMax Lasagna cooler, which
requires an area of 50 cm by 50 cm. Drivers used: Hercules Thriller 3D Drivers
Version 0.81.3539 |
| |
 |
 |
| |
Summary |
| Overclocked stability |
Decent |
| Should you overclock? |
Yes |
| Recommended memory clock: |
65/130 MHz or 67/134 with special cooling |
| Default / Max allowable memory clock: |
65/130 MHz, 75/150 MHz |
| |
|
STB
Velocity 128 |
| Of this group of cards, the Velocity 128, based on the NVIDIA Riva 128,
scales the best overall. The card does especially well in Forsaken. As you can
see in the graphs, there is almost a linear relationship between performance and clock
speed. Without any special cooling, I was able to push the Velocity to 120 MHz.
After that, Quake II and Forsaken tests freeze not long after starting. Quake
II was 7% faster at 120 MHz, while Forsaken was almost 15% faster. In addition to
changing the memory clock, there was also an option in PowerStrip that allows for fast
memory timing for the card, but activating it garbled up the screen, so I didn't bother
testing with it on. Drivers used: NVIDIA driver version 2.0 |
| |
 |
 |
| |
Summary |
| Overclocked stability |
Very good |
| Should you overclock? |
Yes |
| Recommended memory clock: |
110 MHz or 115 MHz if you have good cooling |
| Default / Max allowable memory clock: |
100 MHz, 125 MHz |
| |
|
Some Cooling Tips |
| I
was going to put out a full fledged cooling article, but now I think that's probably not
necessary. Instead I'm going to list some general tips for cooling here- thrown in
for free ;-): |
- Keep your case ventilated! This means
if your power supply and fans are blowing air into the case, you should have some openings
in the case so that the hot air can exit. For instance, if you have a second fan
blowing across your expansion cards, it may be a good idea to take off one of those slot
covers so that the moving air comes out of the case after sweeping across the boards.
Also if you have multiple fans, it is a good idea to have one of them blow air out
of the case.
- Use multiple fans. If your case allows
for a second fan, then by all means put one in. Usually a second fan costs only $10.
For even better results, you can also creatively attach several more fans onto your
case by using those plastic tie-wraps.
- Use dedicated cooling solutions. For
those of you with 7200 RPM drives, it might be a good idea to get one of those hard drive
coolers. Voodoo 2 owners may also want to consider the TennMax Stealth V2 for
improved stability playing games such as Unreal.
- Use a conventional cooling fan. Most of
you may not want to do this, but those of you crazy enough may want to use a human cooling
fan to achieve truly exceptional cooling. Simply open up the side of your tower case
and place one of those 12" fans next to it- works like magic. If the fan and
your computer is right next to an open window, the results will be even better. The
noise of the fan can get annoying, however. [update]
Although I have had no problem, to avoid magnetic interference, you should keep the
fan at least 6" to 12" (or 15 to 30 cm) away from the computer. Thanks to
Sheikh for pointing this out.
|
[ Back to How-to Articles |
Sections Index ]
|
|
