MSI MPG X870E Carbon WiFi Review – Stable workhorse with experience report, teardown, material test and thermal modding

Now let’s do something that none of my colleagues have done before me: I check the promise with the advertised thermal compound. Because we’ve already guessed it: As always, the information is without guarantee (and realistic background). Of course, the degree of compression and the pressure actually exerted must also be taken into account, because the more you compress the pads, the better they get. This is age-old wisdom, which is why I also measure the bulk thermal conductivity with the corrected measurement curves at the end, but I am initially interested in the effective thermal conductivity for the actual layer thicknesses. And because I find it interesting, I also include the pads for the coils in the test, because the purpose of these pads is completely different. Cooling yes, but wasn’t there something else? Exactly: beep, beep… (or not)

Effective thermal resistance

Let’s start with the measurements of the two pads, whereby the advertising claim should only apply to the VRM pads, because the pads for the coils have something else, something very solid on them. Measuring used pads is one of those things, so I carefully lifted them off, “pressed them up” again before measuring and even had to place the VRM pads next to each other so that I could reach the 100 mm² measuring area.

However, I did not include the initial height of 1750 µm because of the possible measurement errors, but started with 1500 µm for both pads, which also roughly corresponds to the thickness between the MOSFET and the cooler base. So only the ranges between 1000 µm and 1500 µm are really useful for comparison with the Thermal Putty Hardwareliebe Extreme64 (Tputty 607), which was also tested. I took the relabeled Tputty 607 as a comparison because it has a real 7.5 W/m-K bulk thermal conductivity and was specified by the manufacturer as at least 6.4 W/m-K (which is correct).

Let’s start with the thermal resistance. We can see that the pad on the VRM performs significantly better than the pad on the coils. But even the better pad does not come close to the thermal putty. We also see that the relevant range above 1000 µm decreases significantly.

I have now compared the relevant layer thicknesses from 800 to 1500 µm as a bar chart for _Rth, so you can see it even more clearly:

Effective thermal conductivity

Let’s now look at the effective thermal conductivity. Once again, we see how the values change over the BLT, although we can no longer expect a linear curve here due to the included area and BLT.

Of course, the whole thing is also shown again as a bar chart for the most important layer thicknesses:

However, while the flexible and well-distributable Thermal Putty performs quite consistently, we can also see here that the data for the VRM pad has been extremely embellished. It’s simply not 7 W/m-K, you have to admit that. I have no idea under which idealized conditions this value was determined, but honest manufacturers measure as I do (and Laird with the Tputty). I have tried to reduce the measurements to the best performing BLTs and even excluded the BLTs used in practice.

At around 5 W/m-K under idealized conditions and around 2.9 W/m-K, you’re not setting any records here, but at least the pad on the VRM is good, because the advertised 7 W/m-K is practically for the gallery. Normal pads usually have 3 to 4 W/m-K, so you have to give MSI credit for having installed something better than the usual average here. However, the marketing was once again far too euphoric, but that’s nothing new, unfortunately. The pad on the coils is as hard as a board and less conductive, but more adhesive. We’ll find out why and what for in the material analysis.

Microscopy and material analysis

Let’s look at the pads first. The pad for the VRM is slightly softer than the one for the coils, but both pads can still be described as rather hard. The pad for the coils is extremely sticky and does not compress as well. This makes it ideal for damping possible vibrations of the coil housings, which was certainly chosen on purpose. After all, we know what it sounds like when the Lorentz forces are released in the coils. Here, the voltage transformer noises are barely perceptible, if at all. The VRM pad has metallic oxide particles of up to 15 µm, but most of them are significantly smaller (3 to 8 µm). The coil pad, on the other hand, has up to 25 µm.

Which brings us finally to the material analysis. Because there are always questions from the community about the carbon contained and bound in the polymer, I have included it. And no: NO carbon particles in the form of graphite have been added, this comes solely from the binding matrix. This also applies to the hydrogen. In the VRM pad, we see Al2O3 and ZnO, i.e. aluminum and zinc oxide, as heat-conducting particles…

…while the coil pad has to make do with only a few coarse particles of AL2O3. This also explains the rather stubborn and firm consistency.

Interim conclusion and modding on thermal putty

Yes, MSI uses significantly better pads on the voltage converters, which are far above the usual average, but the stated 7 W/m-K is a nicely calculated marketing value that shouldn’t be taken too seriously. However, I assume that MSI has simply used the OEM’s data sheet here and this has nothing to do with reality. There are honest manufacturers and some who want to be better than their competitors, even if they are not. But it is positive to see that MSI has thought about the pads. What’s on offer is really good for a factory assembly, but after disassembly the pads are of course no longer usable.

That’s exactly why I modified the board AFTER all the tests with thermal putty. Yes, you can do that, but please note that you may lose your warranty. First form a roll of putty that is really thick enough to fill all the gaps well after pressing it together.

With good putty, there is no need to worry about too much pressure and possible damage to the components. It also covers and fills all the gaps that a solid pad cannot reach. I took the radiator down again after pressing for the photo:

Once assembled, everything that is superfluous simply oozes out and can be CAREFULLY removed with a spatula if necessary. However, the putty that has been squeezed out can’t do any damage, so you can actually leave it on. Like me, because convenience comes first. Speaking of which, this of course also applies to various mounting features, so please turn the page again quickly!