Video Card Overclocking Guide and Analysis

Video Card Overclocking Guide and Analysis
Posted :: May 26, 2004 by Haggs

Introduction:
So you've heard about overclocking and all of the glorious things it can do for your system's performance. We set out to find out just how much extra performance we could safely squeeze out of our Radeon 9800. Our overclocking experiment showed that the card was able to produce between one and two extra frames per second on average in AquaMark3 and Gun Metal BenchMark 2. In 3DMark2001 SE the performance only increased by approximately one percent, while in 3DMark03 the increase was a significant 12 percent. We suspect that the variance in increase between the two marks resulted from ATI's shifted focus from Directx 8 to Directx 9 with their recent Catalyst driver releases.

Test System Specs:

Processor: AMD XP2700+ cooled with Thermaltake Volcano 11+
Memory: 512M DDR PC2700
Motherboard: MSI KT4V with onboard 10/100LAN + AC '97 Audio
Sound Card: Creative Labs Audigy 2 ZS
Power Supply: Antec 400 Watts "SL400"
Primary Monitor: Dell UltraSharp 1800FP 18" LCD (disabled for these tests)
Secondary Monitor: Mag Innovision 986FS 19" CRT
Speakers: Logitech 400Watt 4.1
Video Card: 128MB ATI Radeon 9800 AGP 8x by Sapphire Tech (Directx9.0b) on ATI's Catalyst 4.5 Driver.
Hard Drive 1: Maxtor 60 GB w/2MB Cache (for Windows only)
Hard Drive 2: Seagate 160 GB w/8MB Cache (for everything else)
DVD-ROM: 16x
CD-RW: 52x24x52x
Operating System: Updated Windows XP Professional w/SP1

Setup:
We began the overclocking project by removing ATI's SMARTGART tool. SMARTGART is a part of the Catalyst driver that ensures that your video card runs at stable speeds. Since we were going to be pushing our card to its maximum, we didn't want SMARTGART getting in the way. ATI has a small program available for download that will allow users to remove their SMARTGART safety net feature. Please note that ATI does not recommend removing SMARTGART from your system because it could result in system instability.

This first image shows a portion of the uninstall message that comes up when removing SMARTGART.

Here we are again with yet another warning before SMARTGART is actually removed.

After removing SMARTGART we downloaded the latest version of Rage3D Tweak (version 3.9c). There are a few video card overclocking utilities on the internet, but Rage3D Tweak, an ATI only application, is our favorite (and we couldn't help but install the anime skin for it). There are a handful of nVidia and non-specific video card overclocking programs out there, so don't worry! The stock (non-overclocked) core and memory clocks were 324MHz and 290.25MHz respectively.

The Overclocker tab initially defaults to the video card's current speed. In this case it is the stock speed for the core is 324MHz and the stock speed for the memory is 290.25MHz.
Using the Radeon 9800's stock speeds, we ran the following benchmarks in order: 3DMark2001 SE, 3DMark03, AquaMark3, and Gun Metal BenchMark 2.

Next we ran a flashy 3D render so that we could keep tabs on the status of the video card as we moved the overclocker's sliders to the right. The rendering program can be downloaded here. The render is used to know if the card has been overclocked too high. If the colors become distorted (usually white blotches or flashes) then the core clock speed is too high, and if the render flickers then the memory clock speed is too high.

This is just a screenshot to give you an idea of what the render looks like while it runs.

While keeping the render running in a visible window behind the Rage 3D Tweak overclocker, we slowly moved the sliders to the right in increments of 5MHz. After increasing both the core and memory clock 5MHz each we clicked the apply button and carefully watched the render. We continued this process till it began to flicker, which meant we were within 5MHz of our memory's maximum clock speed. We then brought the memory slider back down 5MHz and hit apply again to make sure everything was stable. Now, while keeping the core clock constant, we raised the memory clock in increments of 1MHz till it flickered again. After setting the memory clock back down 1MHz we had found its maximum stable speed. Next, we did the same procedure (raising in increments of 5MHz, then bumping it back down and going up by 1's) for the core speed till it reached its max. Our Radeon 9800 was able to achieve a maximum stable core speed of 384.75MHz and a maximum memory speed of 333MHz.

After reaching a maximum stable overclock of a 384.75MHz core speed and a 333MHz memory speed we were ready to run our benchmark set again.

The Radeon 9800's core was able to be stably overclocked 16% and the memory was overclocked 13%. We were finally ready to begin running our benchmark set again in the same order as before (3DMark2001 SE, 3DMark03, AquaMark3, and Gun Metal Benchmark 2).