Temperature spike after cpu fan replacement to oem motherboard.

[Gyustarr]

Greetings. Today I swapped my PC's cpu fan which had also an attached backplate glued to the other side of the mobo. After an hour of wiggling I somehow managed to remove it without damaging the mobo. Or so I hope.I cleaned the cpu with isopropyl alcohol, I added a Hyper Tx3i with arctic silver 5, had the fan face outwards to the back with nothing obstructing it's airflow.
Unfortunately, the PC idles at 50-55c(122-131 Fahrenheit) according to speedfan.
One thing to note is that the new fan doesn't go over 1200rpm even at the aforementioned temperatures, and only cracks 1900rpm(max 2500) if the cpu workload hits 100%.
What could be the cause of this?

 

[Eximo]

What CPU, what motherboard, and what cooler did you replace?

Even with a small TX3 I would expect better idle temperatures.

Arctic Silver 5 does have a curing period, so it may improve over time, but not that much. I suspect a lack of clamping force between the cooler and the CPU. Remove the cooler and check the spread on the thermal compound.

 

[Gyustarr]

What CPU, what motherboard, and what cooler did you replace?

Even with a small TX3 I would expect better idle temperatures.

Arctic Silver 5 does have a curing period, so it may improve over time, but not that much. I suspect a lack of clamping force between the cooler and the CPU. Remove the cooler and check the spread on the thermal compound.

It's an old wg43m matx mobo from 2010, with a q9650 cpu. The stock cooler which I replaced was making some ungodly noise. I suppose I'll wait a few hours to see if there's any improvement. After that I'll start fiddling again with the cooler.
EDIT: I forgot to mention that the adhesive pad holding the backplate into place is still intact on the mobo. Could it be retaining heat without the backplate?

 

[Eximo]

I don't think that is the problem. I suspect that the cooler isn't down far enough to keep pressure on the CPU. Tolerances in these sorts of things can be off slightly. The culprit is usually abnormally thin motherboards, which I have run into before with ASUS and Corsair coolers.

Add washers to the back of the motherboard (the glue pad is actually quite convenient for this to prevent shorting) I suggest some thin metal washers. You might have to push down a little harder on the push pins, but it will hopefully increase the clamping pressure.

My other recommendation would be a cooler that comes with a backplate.

 

[Gyustarr]

I don't think that is the problem. I suspect that the cooler isn't down far enough to keep pressure on the CPU. Tolerances in these sorts of things can be off slightly. The culprit is usually abnormally thin motherboards, which I have run into before with ASUS and Corsair coolers.

Add washers to the back of the motherboard (the glue pad is actually quite convenient for this to prevent shorting) I suggest some thin metal washers. You might have to push down a little harder on the push pins, but it will hopefully increase the clamping pressure.

My other recommendation would be a cooler that comes with a backplate.

Thank you for your time. I agree with the motherboard being too thin for the fan to properly be attached, as those old oem mobos were never supposed to leave their custom build cases.