Temps go a little higher after applying arctic mx-4

[janssenerik14]

Hi guys!, i was a little unsecure about this whole situation. So i have a intel core i7 4790. And idle it was about 40c and when i was streaming and playing games and stuff it was about 65c-75c. My PC is 2 years old so i decided to clean with compressed air and change the thermal paste (Arctic mx-4) So i did all of that but now my idle temps are 45c-50c. I am asking cuz on the box it said "no curing time" So do i have to give it some time? is there any reason to worry?

 

[shmoochie]

A lot of temp differences like that come from installation error like little air bubbles, too much/too little paste, or a loose cooler. That's why people that test different compounds and coolers have to reseat the cooler between each test. You might just try redoing it a couple of times to see if it fixes it.

 

[janssenerik14]

A lot of temp differences like that come from installation error like little air bubbles, too much/too little paste, or a loose cooler. That's why people that test different compounds and coolers have to reseat the cooler between each test. You might just try redoing it a couple of times to see if it fixes it.

thx for the fast answer but i have an intel stock cooler and its a pain in the ass to install that again. But are the airbubbles a problem? and when yes how do i prevent them?

 

[shmoochie]

Most air bubbles come from people spreading the thermal paste out themselves instead of using the pressure from the cooler to spread it, but too much paste is often a problem too. Download software that monitors the temps of each core like hwinfo and make sure all the cores are around the same temp. Air bubbles often insulate a single core.

Artic has several different methods for application. The video showing them is on the MX-4 website here: https://www.arctic.ac/us_en/mx-4.html

 

[janssenerik14]

I let the cooler spread it and my core #0 is on 42c while my other cores are at around 37-39c so still normal and no signs for bubbles right?

 

[razamatraz]

MX-4 is one of the best non-metallic compounds out there. It will improve a little over time but not more than 2C or so. It certainly shouldn't be increasing the temp over stock paste (although you didn't mention what was on it before.) I suspect this is a case of too much or too little paste or maybe a cooler that isn't quite seated.

Is it the stock cooler? Did you clean the cooler and CPU with isopropyl alcohol after removing it? Did you pull the cooler after applying paste to see the coverage? Was it covering the whole IHS, running off the sides etc? At 2 years I'd recommend cleaning the heatsink and fan blades with an old toothbrush; just air will get a lot of the stuff, but it tends to get greasy and stick to the aluminum and a good brushing will get a lot more of it.

(Update, you answered some questions while I was typing). I highly suggest a brush cleaning of the stock heatsink, they get "sticky" frankly. I'd also suggest pulling it at least once just to make sure the amount you applied was the right amount (and covers the whole thing to the edges but not more. Yes, it's a pain but if your temps went up after a cleaning something isn't quite right.

 

[Solandri]

The vast majority of heat transfer between the CPU's heat spreader to the heat sink is via metal-on-metal contact. That's why you can mount the heatsink with no thermal paste and still run the computer.

The only role of the thermal paste is to fill in microscopic air gaps which form between the two metal surfaces because the surfaces are not perfectly flat and smooth. You want as little thermal paste as possible - just enough to fill in air gaps. The amount recommended by thermal paste manufacturers is almost universally way too much. They want you to use too much so they can sell you more paste.

You do not want a layer of thermal paste like you're putting mayonnaise on a sandwich. Thermal paste is about two orders of magnitude better at transferring heat than air, which is why it's used. But metal-on-metal is about two orders of magnitude better at transferring heat than thermal paste. So if you use too much paste, you'll reduce the amount of metal-on-metal contact and actually make the CPU run hotter. If you have enough paste on there for an air bubble to form, you have too much paste to begin with.

Generally I use about a half-pea sized dollop of paste, then slide and twist the heatsink around as I press it down. This spreads the paste out and the excess starts to ooze out the sides. When I start to feel metal grinding on metal, then I know I have metal-on-metal contact, and I strap it down. (The compression straps' function is to bend down small metal peaks and ridges on the heatsink and CPU. Without compression, these peaks would separate the two surfaces further, reducing the amount of metal-on-metal contact). You can do a couple practice rounds. Apply, then lift it and check out its spread, to make sure your twisting and sliding motion is producing even coverage. Then wipe it off and start over. You'll probably find that even with a half-pea sized dollop, the majority of the paste still gets pushed out the sides.

The other possibility is you've got debris like hair or dust or a grain of dirt in there. Debris will tilt the heatsink relative to the CPU, causing a reduction in metal-on-metal contact, and thus higher temps. Make sure the inside of your PC and the two surfaces are clean before you apply paste.

 

[janssenerik14]

I had to pull it multiple times cuz i had some problems with the very crapy pins on the cooler so the whole cpu is covered and its a prebuilt system and they didnt tell me wich paste was on there before so u said it should get better about 2c and that will be about my normal temperature. btw i am asking all of these questions cuz its my first time on actually doing something on a PC and yes i did whipe the old paste of with alcohol and i cleaned it a few time before changing the paste. And i applied like a little bean and let the cooler to the rest btw is there another way to notice air bubbles?

 

[Eximo]

If the CPU is not overheating, don't worry about it. If you want lower temperatures, buy a larger cooler. It will be quieter as well.

I consider Arctic MX-4 a good universal thermal compound, suitable for GPUs, CPUs and many different types of surface finishes. Not sure it is ideal for the stock Intel cooler though. That has a pretty well machined surface that might prefer a more liquid compound.

If you are concerned, you can always remove it, clean it again, and see if it does better. But for around $30 you can get any number of cooling solutions that are far better.

 

[janssenerik14]

ok thx man. And btw i noticed that one of my cores is always about 3-5c hotter than the others does that mean something?

 

[Eximo]

This is kind of common on Intel CPUs, The heatspreaders aren't perfectly flat, there is thermal compound underneath them, and some silicon just runs hotter than others. No real way to tell. When it is an extreme difference you either have installed the cooler at a slight angle or there is a thermal compound defect under the heatspreader. Delidding and re-applying paste between the heatspreader and CPU can help.

My 7700k certainly benefited from a de-lidding. I applied some premium thermal compound (not liquid metal) and brought my one errant core closer into line with the others. Still my hottest core is about 3-4C higher than the others.

Intel also creates boost profiles for each CPU. They identify which core is most efficient and will give that one more tasks or keep it boosted longer. So sometimes it is just the way they built the CPU.

 

[razamatraz]

yah, I think you're fine. If you run it for a week and it gets hotter then you might have an issue, but if it gets a couple degrees cooler that's well within spec for a 4790 . If you can give it a bit of a light twisting action as Solandri mentioned to kind of squish it down you might speed it up. Stock coolers don't have the best compression so it might take a while to get it thinned out.

 

[janssenerik14]

Ok i did some stress testing with aida64... and only stressing cpu got 71-72c i stressed 3 mins and it was a pretty constant 72c. So then i stressed cpu and fpu wich got up to 89c and then i stopped the test cuz i didnt want something to brake. So i did apply the thermal paste incorrect now right?

 

[razamatraz]

Ok i did some stress testing with aida64... and only stressing cpu got 71-72c i stressed 3 mins and it was a pretty constant 72c. So then i stressed cpu and fpu wich got up to 89c and then i stopped the test cuz i didnt want something to brake. So i did apply the thermal paste incorrect now right?

That seems a little hot but keep in mind that an AIDA 64 FPU test is a totally unrealistic scenario. Did you run that test before you changed the compound?

The 4790 is an 84W TDP chip (And TDP actually meant something then) and according to the datasheets has a max Tcase (Temperature at the center of the IHS) of 72.72C at full power draw. The core temps will often spike much higher than that though and can actually take up to 100C for brief periods. Is it thermally throttling when it gets that hot? If not you are totally fine. If it is you might still be fine; Intel stock coolers really are just built to work right on the edge under normal conditions. So, this seems like it is probably normal to me and you'd never see that temp under actual loads (even heavy loads like video processing).

If it still worries you there are only a couple of things left you can do:

1. Try again. Pull the cooler, clean it, reapply thermal place and put it back on again. A bit of a pain but stock coolers aren't that hard; turn 4 screw 90 degrees left and pop the pegs out. If the thermal compound was spread out past the edges then put less on next time, if it was not reaching the edges put a little more. Turn the "screws" back 90 degrees clockwise, put the cooler on and press the pins into the holes in a crosswise pattern (IE top left then bottom right then top right then bottom left). Give it a gentle twist back and forth 10 or so times and good to go.

2. Get a better cooler. In general I would just say a cheap tower like a Hyper 212, but you said this is a prebuilt machine so you need to make sure it fits the case (not too tall) and the board (no memory interference), and if there is ducting (like a vent to outside the case right on top of the CPU, which is common in prebuilts) you might have to remove it. These are in the $20-$30 range and easily have double the cooling power of stock; almost any cooler you get from a reasonable brand is better than stock by a long ways and quieter.

I think you are probably fine, but there a couple of options if you're still not comfortable.