Anti-Extreme Overclocking: Problem and Approach
Our problem is simple: we need to find a way to reduce the heat dissipation of the graphics card, at the same time keeping it stable. Overclockers know that the relation between power consumption and heat dissipation of a central processor and its frequency is nearly linear. There are physical reasons for that: processors consume the largest portion of their total power in current surges when switching logical elements made from CMOS transistors. The higher the clock-rate, the more switches per second there are, and accordingly, the higher is the power consumption/heat dissipation. Thus, one of the ways to reduce the generated heat is to reduce the clock rate.
This is not our way, though. People who are into extreme overclocking certainly know that the CPU or GPU generates more heat when its voltage has been increased than when you overclock it without increasing the core voltage. This is another fact, explained by Ohm’s law: the relation between the power consumption/heat dissipation of a processor and its voltage is not linear, but rather quadratic.
Thus, it is better to oppose the high heat dissipation of an electronic chip by reducing its voltage rather than by reducing its operational frequency. We can leave the clock rate alone and reword our problem a little bit: our task is to reduce the amount of heat generated by the graphics card by reducing the voltages of the GPU and graphics memory while keeping the card stable at its nominal frequencies.
Testbed and Methods
The testbed configuration looks as follows:
- Intel Pentium 4 3000MHz CPU;
- ASUS P4C800 mainboard (i875 chipset);
- 2x512MB PC3200 DDR SDRAM by TwinMOS, CL2.5.
We used the following software:
- Microsoft Windows XP Pro SP1;
- DirectX 9.0b;
- Catalyst version 4.1 driver.
I tested the graphics cards in an open testbed rather than in a system case and without any additional air cooling. I chose this test method as a compromise since each particular model of a system case may have affected the results in a certain way. Available system cases differ greatly in the thermal environment they provide for the devices inside, but graphics cards usually have lower temperatures in well-designed cases with proper airflows than in an open testbed. Thus, it is even harder for the graphics card to work in an open testbed without extra cooling than in a good system case. Please, keep this fact in mind.