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Alphacool Apex thermal paste in-depth Review – No absolute top values, but long-term stability and good

27. June 2024 06:00

Let’s solve the “mystery” surrounding the reference paste used in the basic article today and yes, it is the paste that you can now also buy as Alphacool Apex. Of course, you have to remain objective and not take the manufacturer’s specifications completely seriously, because here too, marketing has of course poured a good portion of wishful thinking into the stated thermal conductivity with a large ladle. However, we have already learned why this value is not so important in the two basic articles (see link).

There are several important reasons why I use this paste as a reference, none of which have anything to do with Alphacool. This paste comes from a real, large manufacturer and not a bottler, which guarantees me consistent quality over a longer period of time. After all, I still need to be able to obtain the reference in this form in 2 or 3 years’ time. In addition, their chemical composition makes them quite stable over time, so that I have been using them on various hardware, e.g. graphics cards, for a very long time. Many significantly more powerful pastes often lose their performance after just 6 to 9 months, which is enough for great benchmarks at the beginning, but only causes new problems for the customer in the end. And I already had this paste in test systems when it was not yet available in stores as Alphacool Apex.

Even if the following quote comes from another manufacturer, I simply have to emphasize that Arctic is the only manufacturer to date that explains the values for thermal conductivity correctly or does not even embellish them. The FAQ on the Arctic homepage is therefore generally worth quoting in full, as it not only speaks to me from the heart, but is also absolutely consistent with my laboratory measurements. Much more than 4 W/(m-K) is not possible at all with conventional pastes. Because it is so beautifully honest, I will use this part from now on as a standard quote in all paste tests of all manufacturers and place it in front. You can’t bend physics.

Why does ARCTIC not communicate any values for thermal conductivity?

ARCTIC has deliberately decided not to specify any values for the thermal conductivity of thermal pastes and thermal pads, as many manufacturers invent, artificially inflate or embellish this value. Thermally conductive paste has a thermal conductivity of 1 to 4 W/mK. Values outside this range, such as 12.5 W/mK, do not correspond to the truth. Many competitors state values above 4 W/mK to suggest better performance. This often leads to false expectations and dissatisfied users. ARCTIC offers its customers innovative thermal conductive materials at the best possible price-performance ratio instead of relying on manipulated performance data.
-Arctic-

Unboxing

There’s not really much to write here, because you don’t have to unpack what’s not inside. Apart from the tube there is nothing, not even a spatula. But whether you really need one remains to be seen, because anyone who likes blobs or drawing lines will consider this to be unintentionally sustainable. In any case, the plastic insert is not; a pure cardboard box would have been much more environmentally friendly.

Technical data

Let’s leave the marketing aside and look at the technical data of this paste, which is available in various containers and sizes. We can see that the information on thermal conductivity has nothing to do with reality. The columns highlighted in green contain measured values, the columns highlighted in gray contain the manufacturer’s specifications, which look plausible so far.

Technical data
Bulk thermal conductivity λ	17 W/(m-K) Marketing
Effective thermal conductivity λeff_,	2.885 W/(m-K) (test method ASTM D5470-10)
Effective thermal resistance _Rth400 µm	1.49730 mm²K/W (Test method ASTM D5470-10)
Effective thermal resistance _Rth200 µm	0.79820 mm²K/W (Test method ASTM D5470-10)
Effective thermal resistance _Rth100 µm	0.45822 mm²K/W (Test method ASTM D5470-10)
Effective thermal resistance _Rthmin	0.12552 mm²K/W (Test method ASTM D5470-10)
Minimum thickness	10 µm (at 60 PSI and 60 °C after 30 minutes)
Heat conducting particles	Corundum_(AL2O3) (Test method LIBS, Keyence EA-300)
Volatilization rate (volatilization)	(24h@200 °C)% less than 0.5
Density	3.2 g/cc (Test method ASTM D792)
Viscosity	150~200*10³ mPa.s (Test method ASTM D2196)
Working temperature	-40 °C to 120 °C
Breakdown Voltage	250 V/mil (Test method ASTM D149)
Thermal Impedance	0.1 /- 0.01 °C in 2/W (Test method ASTM D5470)
Maximum pressure	40 PSI
Color	Gray
Accessories	None
Container	Tube 1 g, 4 g Tin 20 g, 50 g, 100 g

Further links and basics

The Ultimate Thermal Paste and Pad Compendium: Application, Ingredients, Manufacturing, Optimization, Aging, Profit Margins and Marketing

Real laboratory tests of thermal pastes on igor’sLAB – Part 1 – Measurement setup and methodology

Real laboratory tests of thermal pastes on igor’sLAB – Part 2 – First comparative measurement with 2 expensive pastes

Alphacool Apex Wärmeleitpaste, 1g (13037)

	Lagernd im Außenlager, Lieferung 2-3 WerktageStand: 18.04.25 12:50	1,82 €*Stand: 18.04.25 12:52
	lagernd: 250+	1,87 €*Stand: 18.04.25 12:44
	Auf Lager	1,89 €*Stand: 18.04.25 12:54