ACS² Does Provide Superior GPU & Memory Cooling
ACS² Cooling Unit
6 May 2002
EVGA.com Engineering

Several hardware review sites have had a difference of opinion regarding the ACS²’s cooling ability. While we have a great deal of respect for their reviews and their unbiased natures, we do have some question about the testing methods that they employed.

In the tests that were conducted by the review sites, the actual temperature measured was the back of the PCB, and not the temperature of the GPU or the memory chips. Normally this would have been a fairly accurate way to show the temperature differences, however the ACS² uses a plate on the back of the card that alters the thermal properties of the PCB. When the heat from the rear memory transfers to that cooling plate, it gets hotter, and due to its proximity to the back of the card it causes the PCB temperature in that area to be higher as well.

During the ACS² developement process it underwent constant testing in order to verify cooling capabilities. It was the data gathered from these test that guided us in our efforts to refine the ACS^2. In order to demonstrate the way that we arrived at the actual temperatures of the GPU and the memory, we have organized some of our original test data in to a testing and procedures report that shows in detail the way and manner that were able to determine that the ACS² does indeed provide superior GPU & Memory cooling.

ACS² Cooling Device Rev C (Proto Type - Provided to Review Sites)

• Dimensions: 106.2mm Length x 94.7mm Width x 11.7mm Height
• Weight: 110 g
• Material: Al 6063 (nickel plating) / SUS304
  • Heat Pipe with solder interface material between staked fins, heat pipe, and heatsink
  • Ram 1, 2, 3, 4 with thermal pad (softtherm 86/200, t=0.5mm)
  • GPU with grease (Sil-More SC102)

Fan (Delta)
Size: 37mm x 37mm x 10mm
Rated Voltage: 12 Volt
Rated Speed: 5500 ± 10% RPM
Bearing Type: Two ball bearings

Back Plate

• Dimensions: 79.6mm Length x 71.25mm Width x 1.9mm Height
• Weight: 30 g
• Material: Al 1050
  • Heat Pipe with solder interface material between stacked find, heat pipe, and plate
  • Ram 5 with thermal pad (softtherm 86/200, t=0.8mm)
  • Ram 6, 7, 8 with thermal pad (fujipoly sarcon, t=1.0mm)

ACS2 Rev C Front Plate Front		ACS2 Rev C Front Plate Back
ACS2 Rev C Back Plate Front		ACS2 Rev C Back Plate Back
Delta Fan

ACS² Cooling Device Rev E (Production)

• Dimensions: 106.2mm Length x 94.7mm Width x 11.7mm Height
• Weight: 90 g
• Material: Al 6063 (nickel plating) / SUS304
  • Heat Pipe with solder interface material between staked fins, heat pipe, and heatsink
  • Ram 1, 2, 3, 4 with thermal gap filler (AOS 52042)
    
  • GPU with grease (Sil-More SC102)
    
    

  Fan (Delta)

  • Size: 37mm x 37mm x 10mm
  • Rated Voltage: 12 Volt
  • Rated Speed: 5500 ± 10% RPM
  • Bearing Type: Two ball bearings
    
    

  Back Plate

• Dimensions: 79.6mm Length x 71.25mm Width x 1.9mm Height
• Weight: 30 g
• Material: Al 1050
  • Heat Pipe with solder interface material between stacked find, heat pipe, and plate
  • Ram 5 with thermal pad (softtherm 86/200, t=0.8mm)
  • Ram 6, 7, 8 with thermal pad (fujipoly sarcon, t=1.0mm)

Thermal Pads, Grease, and Filler

• Softtherm 86/200, t=0.5mm
• Softtherm 86/200, t=0.8mm
• Fijipoly Sarcon, t=1.0mm
• Thermal Gap Filler, AOS 52042
• Thermal Grease, Sil-More SC102
• Softtherm 86/200
• Fujipoly Sarcon
• AOS 52042
• Sil-More SC102

Test Conditions
CPU: Intel P4—1.4 GHz
Main Board: Asus P4T
Ram: Rambus 256 MB
HD: IBM 40 GB IDE
VGA Card: EVGA.com e-GeForce4 Ti 4600
Test Software: Quake 3
Test Time: 6 Hours

Thermal Test Instruments

Thermal Test Measure Positions

Thermal Test Pictures

Thermal Test Results

All temperatures are measured in Celsius degrees

ACS² Rev C Test Graph

ACS² Rev E Test Graph