Something odd is going on here and I can't fathom it. I have switched out a Cooler Master Nepton 240M AIO cooler for a Alpenföhn Matterhorn White on a 5820K... but my temps have shot up from low 30s to high 30s/low 40s! I have re-fitted it twice, cleaning and re-applying TIM (Arctic Cooling MX-4, same as I was using before also), but no change. What is going on here? Do I have faulty cooler? I did notice there was a scuff mark on the bottom, but over to one side and I can't see that would affect temps this much!

Edit: AIDA64 stress test has temps hitting around low 80s.

Do I perhaps need to wait a while for the TIM to cure and temps will settle down? Or is that a myth anyway?

I haven't bought a new heat sink in a while (still running a NH-D14 from years ago), but...

Does the idle temperature matter very much? I'd worry more about idle noise as long as the temperature doesn't get silly.

How does the new/old compare for temperature and noise with the system loaded?

Take the ambient temperature into account. It has been warm over the last few days.

Noise is fine, but I have good fans in there, Alpenfohns and Parvum F1s, so they're all pretty quiet... obviously when it ramps up you hear it, but otherwise fine. It's hard to say how it compares though because I had a reference GPU in there before and now it's the ACX cooler on the EVGA 980Ti so much quieter. I think that was probably the noisiest thing in there before. The Nepton 240M was very quiet apart from the pump making noises now and again. I have also swapped the PSU out so that's another factor which is making any noise comparison very difficult.

All I have to go on is this strange temp increase, although from what I'm reading high 30's/low 40's isn't BAD for a 5820k, it's just not great. Maybe the Nepton was just better than I realised lol! I've only swapped it because I'm making the system for my brother and he didn't want the risk of an AIO leaking.

I know it is hot now, which could be a factor, but I looked at it earlier today (before making the swap) and it was still around the low 30's. Cooling should actually be better now in the case, as I took out the Nepton from up front and added x2 140mm Alpenfohn Wing Boost fans on intake.

With respect.... You went from a 240mm rad Water Cooler to a £40 air cooler and can't understand why your temps are up?

You swapped a great cooler for a mediocre one, the new one just isn't as good at cooling at the old one.

Here NZXT KRAKEN X31 just as good as your old one, if not better, and with a smaller RAD.

I'm using it.

humbug said:

With respect.... You went from a 240mm rad Water Cooler to a £40 air cooler and can't understand why your temps are up?

You swapped a great cooler for a mediocre one, the new one just isn't as good at cooling at the old one.

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This... Water conducts heat far more efficiently than air - there is a reason it is in use in the first place. You're unlikely to get the same temperatures using air in place of liquid, closed or custom loop.

Smffy said:

This... Water conducts heat far more efficiently than air - there is a reason it is in use in the first place. You're unlikely to get the same temperatures using air in place of liquid, closed or custom loop.

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It does, but all your radiator is in effect is a large air cooler, the liquid cools the processor but you still need the transfer heat from the radiator to the air. I have gone from a small custom loop with a 240mm radiator to a large air cooler (Silverstone HE01) with a minimal change in temperatures.

It is largely down to airflow in the case when you are air cooling. I use 2 x 140mm intake and 3 x 120mm exhaust.

Idles rising does seem a bit odd? But, i recently switched from high end air, (alpenfohn k2) to an antec h1200 AIO. Temps under intel XTU at 4.5ghz would hit the low 80's with the air cooler, mid 70's with the AIO. Surface area of the k2 is actually a fair bit larger too than the dual rad for the AIO. So liquid is probably helping a bit too.

Smffy said:

This... Water conducts heat far more efficiently than air - there is a reason it is in use in the first place. You're unlikely to get the same temperatures using air in place of liquid, closed or custom loop.

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My NHD15 is just as good as a h100i and is a fair bit quieter, the only ones that cool better are the Thermaltake water 3.0 extreme s and the NZXT Kraken x61 but both are also much louder looking at results.

nkata said:

It does, but all your radiator is in effect is a large air cooler, the liquid cools the processor but you still need the transfer heat from the radiator to the air. I have gone from a small custom loop with a 240mm radiator to a large air cooler (Silverstone HE01) with a minimal change in temperatures.

It is largely down to airflow in the case when you are air cooling. I use 2 x 140mm intake and 3 x 120mm exhaust.

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Airflow is key but the thing to understand about the liquid cooling is that liquid is able to conduct heat far more effectively. In simple terms it will gain and lose heat more effectively, so the fact the air is cooling the radiator fins is irrelevant as its able to remove (conduct) more heat away from the component at a faster rate then lose it faster when it passes round the loop. Its basically doing what the heat sink is doing but with the added bonus of the liquid shifting it all quicker, the rad is the heat sync with fans on just like your air cooler.

240mm is not a small loop for one component... So yeah fact the temps have changed just suggests the air cooler is not as effective at shifting heat in your current case. I don't really see why you would trade liquid for a static CPU block but each to there own, hope you figure out how to make it more suitable bud.

I did expect it to be a bit worse, but was slightly surprised at the amount. That said, it is AWFULLY hot right now, so things may settle. As mentioned, the only reason I changed it was because it's a build for my brother who doesn't want an AIO... I did explain it would cool better but he just doesn't want the risk of leaking or damage, especially as he has kids running about the place.

What rpm is the cpu fan running at idle and load? You might need to adjust the fan profile.

danoliver1 said:

What rpm is the cpu fan running at idle and load? You might need to adjust the fan profile.

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Seems to be around the 650RPM mark idle. Under AIDA64 stress test it rises to about 1100.

Smffy said:

I don't really see why you would trade liquid for a static CPU block but each to there own

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Erm.. maybe because the best air coolers are almost as good as the best closed loop coolers and are also much quieter? Nearly every review site will tell you this, AIO's are good for space saving but obviously have their downsides. I would rather a big bulky quiet cooler rather than more noise tbh.

Smffy said:

Airflow is key but the thing to understand about the liquid cooling is that liquid is able to conduct heat far more effectively. In simple terms it will gain and lose heat more effectively, so the fact the air is cooling the radiator fins is irrelevant as its able to remove (conduct) more heat away from the component at a faster rate then lose it faster when it passes round the loop. Its basically doing what the heat sink is doing but with the added bonus of the liquid shifting it all quicker, the rad is the heat sync with fans on just like your air cooler.

240mm is not a small loop for one component... So yeah fact the temps have changed just suggests the air cooler is not as effective at shifting heat in your current case. I don't really see why you would trade liquid for a static CPU block but each to there own, hope you figure out how to make it more suitable bud.

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What? The rad is far from irrelevant, it's what makes water cooling good - large rad space that is on the edge of the case. The water moving the heat away is just to enable this, it's not any more effective at conducting heat than the phase change heat pipes that take the heat away from the core on a high-end air cooler but they only take it a short distance. The downsides of an air cooler are a result of this short distance & lack of flexibility - the heavy cooler is attached to the mobo and can be in the way plus being internal to the case is at the mercy of poor overall case airflow.

A well set up air cooler properly fed matches most AIOs on temps and beats them on noise just fine as others have demonstrated with links.