Thermal paste & pad comparison (MX4, Graphite thermal pads from IC and Panasonic)

maukka · 2019-04-26T10:38:46.000Z

Another round of testing with an uneven Chinese heatsink and using low and high clamping power. Loose connection was with the screws just holding the MCPCB put, but not really clamping it down. Tight was with the little screws as tight as was practical.

This time the results were more interesting with the No TIM being horrible. The normal thermal paste performed almost identically with low and high clamping power while the graphite pads shined when the MCPCB was clamped on tight. In that case they were actually outperforming the paste. This could be due to their ability to conduct heat very efficiently in the lateral direction (i.e. the small hotspot generated by the emitter was spread effectively to a larger area).

Ambient temperature was 27°C. Temperature number on the graphs are delta over ambient. I measured both the MCPCB and emitter separately.

No TIM with loose clamping. LED is red line, MCPCB is blue.

No TIM with tight clamping

Panasonic PGS graphite pad with loose clamping

Panasonic PGS graphite pad with tight clamping

IC Graphite pad, loose clamping

IC Graphite pad, tight clamping

MX4 thermal paste, loose clamping

MX4 thermal paste, tight clamping

Output comparison with a 1A output for reference. First with loose clamping. MX4 is marginally better than the pads.

Identical results for the TIMs with the screws tightened

Similar story with the forward voltage. Higher heat equals lower voltage.

Loose clamping

Tight clamping

Conclusion: With less than optimal mating surfaces, if there’s not a lot of clamping power available, use thermal paste (although in practice graphite pads are similar in performance). If secure mounting with lots of clamping power is available, graphite pads are at least as good or even a bit better than paste. No TIM at all is significantly worse in both cases with an uneven heatsink (what a surprise).

The_Driver1 · 2019-05-02T14:11:56.000Z

Thanks for the comprehensive testing and the valuable data! I’ve planning to use such TIM pads for lights that are modded frequently to skip the annoying procedure of removing and reapplying the paste every time.

Could you maybe also test liquid metal thermal paste?

It might make sense to use an Osram White flat for testing.

DB_Custom · 2019-05-02T13:52:02.000Z

Really have to keep Gallium away from Aluminum though, so in the right circumstance it’s useable but not in all cases. I’ve used it in special lights with good results, not sure really without all the fancy measuring equipment if it’s better or worse than just using a good paste. These days when I have a copper to copper interface I usually reflow the MCPCB to the pill…

The_Driver1 · 2019-05-02T14:18:03.000Z

DB Custom:

Really have to keep Gallium away from Aluminum though, so in the right circumstance it’s useable but not in all cases. I’ve used it in special lights with good results, not sure really without all the fancy measuring equipment if it’s better or worse than just using a good paste. These days when I have a copper to copper interface I usually reflow the MCPCB to the pill…

Reflowing can be better actually if you use pure Indium as solder, but it makes repositioning/replacing the LED very labourous.

M3CSL · 2019-05-02T14:12:04.000Z

Thanks for the data, very interesting tests you have carried out!

The_Driver1 · 2019-08-30T16:24:52.000Z

One thing to note here is that Arctic MX4 is a very common thermal paste, but definitely not the best one on the market in terms of pure performance. Testing by pc reviewers has revealed that Thermal Grizzly Kryonaut is currently the highest performing one. When used with CPUs is typically achieves around 3°C less compared to cheap pastes. This might be important for someone trying to overdrive an Osram White Flat or similar.

Phlogiston · 2019-09-01T10:47:39.000Z

Always important to cite this trailblazing article in the field of thermal paste comparisons:

http://www.dansdata.com/goop.htm

maukka · 2019-09-01T11:27:58.000Z

Here’s something a bit more recent:

Guru3D.com

Guru3D Thermal Paste Roundup 2019

Thermal paste is an often-overlooked part of most computer setups. You can simply use the pre-applied stuff, or the thermal paste that comes with your motherboard, and still get reasonable processor t... Introduction

TL;DR: it doesn’t matter. MX-4 is still the best for the price.

Agro · 2019-09-01T12:12:11.000Z

maukka:

Here’s something a bit more recent:
Guru3D Thermal Paste Roundup 2019

TL;DR: it doesn’t matter. MX-4 is still the best for the price.

I so wish these comparison included some budget pastes…GD900 gets quite a few recommendations but it’s hard to find it in serious tests.

The_Driver1 · 2019-09-01T14:48:21.000Z

Phlogiston:

Always important to cite this trailblazing article in the field of thermal paste comparisons: http://www.dansdata.com/goop.htm

That's a great article!

Like I already said, a good paste might be interesting when using LEDs with the very highest power densities like the Osram White Flat. Otherwise, no. I've been using the same tube of Arctic Silver 5 for the past 10 years.

These Panasonic thermal pads here are really a much bigger change. No more cleaning!

id30209 · 2019-09-01T13:24:03.000Z

Good info. I just ran out of my AS 5…

led4power · 2019-09-02T06:52:58.000Z

The problem with these high performance pastes, from my experience,is they dry out after 6-12months and then become obviously worse than even the cheap pastes.

All those tests show short term performance with fresh paste, but I'd really like to find good paste with long term performance, the one that doesn't have to be replaced with fresh paste each xx months.

Agro · 2019-09-02T06:56:17.000Z

I remember a certain forum recommending gelid gc extreme for that.

The_Driver1 · 2019-09-02T12:44:26.000Z

led4power:

The problem with these high performance pastes, from my experience,is they dry out after 6-12months and then become obviously worse than even the cheap pastes.

All those tests show short term performance with fresh paste, but I'd really like to find good paste with long term performance, the one that doesn't have to be replaced with fresh paste each xx months.

Do have any data/links on this? Which do you consider a cheap paste and which not?

led4power · 2019-09-02T16:28:45.000Z

I noticed MX-2 and AS5 become dry several months after application in both flashlight and PC. Flashlight OTP triggered at lower than usual body temperature - one of advantages of NTC on LED MCPCB, driver correctly detected OTP threshold level (65C), but because paste was dry body temperature was lower than it should've been.

PC - CPU lags etc., after inspecting paste was also completely dry, this does not happen with generic lower thermal conductivity oil based pastes.

id30209 · 2019-09-02T17:44:30.000Z

Been googling past few days and Gelid truely wins in almost every review plus it won’t dry out in few months due to viscosity. Looks like i found the winner…for now
But a better option is Phobya 2, thermal epoxy though

middle_age_man · 2019-11-30T01:33:25.000Z

Does anyone have experience with MasterGel Maker Nano-High? It’s been favorably reviewed, e.g. Cooler Master MasterGel Maker Nano Review | eTeknix and apparently doesn’t tend to dry up as quickly as other pastes.

gerasalex · 2019-11-30T02:51:58.000Z

I don’t know how this works, but there are many good rumors about Noctua NT-H2 thermal grease

KevinZA1988 · 2019-11-30T05:49:45.000Z

middle age man:

Does anyone have experience with MasterGel Maker Nano-High? It’s been favorably reviewed, e.g. Cooler Master MasterGel Maker Nano Review - eTeknix and apparently doesn’t tend to dry up as quickly as other pastes.

I just finished my 2nd tube and so far it’s been excellent. Opened my D4 after almost 18 months to do another emitter swap and the paste wasn’t dry. The problem is it’s sold out at every supplier in SA for the past 3 months. I should have bought more when I had the opportunity.

id30209 · 2019-11-30T09:57:29.000Z

I got some IC Diamond paste and i was surprised by A LOT how effective this one is.

You can feel the heat much sooner than with any other paste i've tried. Bloody amazing!

Since it's quit thick it doesn't get dry so fast unlike others.

But as soon as i discovered this gem, i've start soldering MCPCBs... THE BEST solution for heat transfer!