Running a cpu with a heatsink but no attached fan......

[spoony77]

Hi people
So I just moved my htpc into a mini itx case the sugo sg13 and have come up against an issue where my cpu with its heatsink on only has 15mm clearance to the psu. (won't fit with the standard fan on)
I have pointed the fan of the psu down so It exhausts/sucks air away from the heatsink.
Will this setup be OK for a htpc with some light gaming?
I really don't want to have to buy an AIO cooler but I have seen some low profile 15mm fans but I'd have to somehow glue/wedge it to the heatsink as there is not enough room in this tiny case for the required 120mm fan that fits this heatsink.
What do you guys think?
Kind regards

 

[Mcnumpty2323]

Test it and see temperatures
Guess which cpu will matter
But ideally probably want a fan on it
But if its a low power cpu
Not saying its not possible with no fan
But you don't see many fanless heatsinks
For a reason I guess

 

[drakulton]

Depending upon how hot your PSU gets under load, you could take the PSU cover off and flip the PSU fan, so that it now pulls in air from the exhaust vent and blows it directly on the CPU heatsink.

 

[spoony77]

Thanks for the replies guys.
It's an i5 2500k but it won't be overclocked and am happy to undervolt it.
I wondered whether or not I could somehow get the cpu fan to blow rather than suck but then I thought that would be pushing warm air over the fins of the heatsink rather than cool air.
I have a 120mm fan at the front but it's not the mesh version of the case so I'm not sure how effective that will be.
Im gonna switch it on and see what the temps are saying then update this post.....

 

[Mcnumpty2323]

Yeah testing it to see the temps
Is best bet
Never tried undervolting a 2500k
Mine was always overclocked
To the max lol

 

[hornetstinger]

I run my desktop with no CPU fan, but I have a scythe ninja, antec p180 case, case fan is within a couple of cm from the heatsink, and I'm running stock CPU speed, and it is fine and dead quiet, only pay fan GPU is passive also. Amd quad core so runs cool

 

[spoony77]

So I did some tests and it's idling around mid 40s using Intel speedstep and going upto mid 60s under light load so not too bad.
I've set coretemp to turn off the system if it hits 75c so hopefully that should be OK whilst it's winter and I will re-assess in the summer.
Loving this little case though not sure I'll ever buy full size atx again!

 

[Danny75]

Does the motherboard have a power limit throttle? No need for the system to shut down then. Can carry on as it downclocks some so as not to exceed a power limit. Some even have a thermal limit that does the same.

 

[LuckyBenski]

Does the motherboard have a power limit throttle? No need for the system to shut down then. Can carry on as it downclocks some so as not to exceed a power limit. Some even have a thermal limit that does the same.

But how is the power limit related to cooling/temp status?

 

[Danny75]

But how is the power limit related to cooling/temp status?

@LuckyBenski

Example: spoony77 keeps the Coretemp 75C shutdown setting on and starts running Cinebench R20 as he watches TDP and temperature. He will see the TDP value just before each shutdown and bring the power limit down accordingly. Eventually he'll find a general sweet spot that can allow converting a video with Handbrake, or play a demanding game, or whatever he uses it for, with max temps around 70C, without the system shutting down. It will just throttle speed like a laptop. Imo, a better method than potentially avoiding some tasks you'd like the system to do so that the system doesn't shut down.

Interestingly, running Prime Small FFTs can produce lower temps than Cinebench R20 if power is throttled. Saw this with a 3700X set to power limit of 120W (that figure allowed Cinebench R20 to use all it needed while throttling even power-hungrier stuff like Prime). R20 would hit about 79C, and Prime low 70s.

As said, if the motherboard also has a thermal limit (the type that makes it throttle not shut down), then you can also just use that.

 

[spoony77]

The motherboard seems farely basic it's the P8H77-i by Asus and I can't see any power limits in the bios or even temperature limits hence why I'm using coretemp from within windows for the safety cut off

 

[Danny75]

The motherboard seems farely basic it's the P8H77-i by Asus and I can't see any power limits in the bios or even temperature limits hence why I'm using coretemp from within windows for the safety cut off

Gotcha. Yeah the old ones don't tend to. Been messing with an old Lynnfield i5-750 and Asus P7P55D and it didn't have it either. Intel XTU within Windows is another option. Or ThrottleStop. If you ever have a need for this.

 

[hornetstinger]

You could under copy it and unlock it, say it's just for a low power usage