18-way TIM Comparison

Add Your Comments

18 greases compared – Ronald Dy Geronimo

After 3 months of testing, I present this TIM (thermal interface material) comparison featuring 18 different materials in paste, liquid, “stick”, pad and foil forms.

TIMs

The heat source used is an Athlon XP “T-Bred B” 1800+, overclocked to 2410 MHz at 1.75V – heat output is unknown. Die surface area is approximately 85mm². The CPU temperature sensor is a customized LM35 Precision Centigrade Sensor, thermally-coupled to the backside of the processor via epoxy and thermal grease:

Sensor

There are separate LM35 sensors for both ambient air and radiator outlet water temps.

The processor is water-cooled by a copper waterblock that is held by a specially designed clamping mechanism, which delivers force along a single axis towards the center of the processor die:

Clamp

This greatly reduces waterblock mounting variances. The closure force is approximately 24 pounds (the maximum AMD recommended force) which results in approximately 183 psi on the tiny Athlon XP die. Spring compression was kept constant over the test runs.

Test Conditions

  • A CPU loading utility, BurnK7, was used to provide constant, maximized heat output. A special Linux installation on a bootable CD-ROM was used to run BurnK7 so as to minimize any OS interference (see HERE)
  • Each TIM was burned-in for 1 hour @ 55°C (nominal)
  • Each TIM was allowed to “settle” for 24 hours
  • The waterblock was lapped in-between runs in order to remove any residual TIM
  • Second runs were optional

Results are expressed as temperature of CPU probe minus temperature of water probe (Tcpu – Twater), in degrees Celsius. Lower is better, of course.

TIM

1st Run

2nd Run

Average

Remarks

X23-7804E3 (Shin-Etsu MicroSi)

Shin

20.3

20.2

20.25

Thin BLT required, gray paste

Ceramique (Arctic Silver, Inc)

Shin

20.5

20.3

20.4

Sticky, white paste

Radio Shack Silicone HS Comp (metal tube)

Shin

20.6

20.4

20.5

Typical white grease, metal tube

Stars White (Balance Stars)

Stars

20.6

na

20.6

1 run only, typical white grease, “soft pack”, came with generic HSF

X23-7783D-S (Shin-Etsu MicroSi)

Shin

22.5

22.3

22.4

Post-heating required, gray paste

HTC (Electrolube)

HTC

22.6

na

22.6

1 run only, typical white non-silicone grease, expired

Powerfilm Bar (Power Devices – Loctite)

Shin

23.1

22.7

22.9

Black “stick” PCM, crayon-like, WB preheated on application in order to dispense evenly

Radio Shack Silicone HS Comp (plastic tube)

Shin

23.3

na

23.3

1 run only, white grease, less opaque, plastic tube

T-pcm hp105 (Thermagon)

T-pcm

23.5

23.3

23.4

Tacky, white PCM

XTC (Nanotherm)

XTC (Nanotherm)

23.3

23.7

23.5

Silver grease

Stars-700 (Balance Stars)

Stars

25.5

na

25.5

1 run only, silver grease

X23-7798 (Shin-Etsu MicroSi)

Shin

25.8

26.0

25.9

Viscous gray paste

G-751 (Shin-Etsu MicroSi)

Shin

26.5

26.3

26.4

Viscous gray paste

T-grease 2500 (Thermagon)

2500

27.3

na

27.3

1 run only, abrasive, viscous

Bergquist 225F-AC

Bergquist 225F-AC

27.9

na

27.9

1 run only, black PCM coated on aluminum carrier

FSF52 (Orcus, Inc)

Orcus

27.9

na

27.9

1 run only, white PCM, non-tacky

PCM+ (Nanotherm)

PCM

29.1

na

29.1

1 run only, blue suspension, very fluid

Blue II (Nanotherm)

Blue II (Nanotherm)

30.0

31.0

30.5

Blue paste

The best performer overall was the Shin-Etsu MicroSi X23-7804E3, followed by the WHITE greases (Ceramique, Radio Shack metal tube, Stars white). Apparently you can’t go wrong with “generic white goop” as far as performance is concerned, although longevity characteristics are equally important; what may perform well at the onset may deteriorate several months down the road, owing to migration, pump-out and drying issues. Which brings us to the supposedly longer-lasting TIMs, the phase-change materials (PCM).

PCMs are solid at room temperature but soften/liquefy at CPU operating temperatures. The best performing PCM was Power Devices’ Powerfilm, scoring within 3°C of the best grease, performing even better than many of the greases in this roundup. This should lay to rest the notion that all PCMs are very poor performers.

Not all PCMs perform well, though; the FSF52 by Orcus Inc. did poorly, as did Berquist’s Hi-flow 225F-AC due to its aluminum foil carrier.

At the bottom is Nanotherm’s Blue II, the worst performer in this test, retested three times to verify the poor results. Nanotherm’s novel concept PCM+ (new formula) also performed very poorly in this test.

Ronald Dy Geronimo

Leave a Reply

Your email address will not be published. Required fields are marked *