- Joined
- Dec 27, 2008
I put together a mini itx cube build originally using the G3258 GPU overclocked to 4.4 ghz outside of case on the stock Intel cooler. After I installed it in the CM Elite 110 it ran way too hot so I slapped a Noctua NH-L9x65 low profile cooler on it but it still ran too hot. It would quickly climb into the 90s C. when stress testing.
So I down-clocked it and lowered the vcore considerably but it didn't help as much as I needed and now the lower clock speed dinged the performance to the point where I pulled the G3258 and put in an i3 4170 at stock voltage. That gave stress temps in the low 90s, just barely below Tjmax.
I was surprised because the Noctua NH-L9x65 is a fairly hefty hunk of metal for a low profile cooler. As I was looking the situation over I realized the problem was that there was only about 12 mm of space between the bottom of the PSU and the cooler fan. I took it all out of the case and bread boarded it and temps came way down. Did some research on how clearance to fan affects fan performance and discovered that the rule of thumb is that for an axial fan the clearance should be equal to the diameter of the fan. This Noctua cooler has a 92mm fan so that would equate to 46 mm. It's not hard to see that the fan was starved for air.
I can see that with this case the only good choice for cpu cooling is an AOI water so I ordered the Corsair H55 Quiet edition. Uncharacteristically, Amazon bungled the shipment routing and it was sent in the wrong direction so it might be a couple more days before I get it.
But just as an aside I did a little informal experiment with a 140 mm fan I had laying around. I connected it to a PSU and moved it up and down off a table top at various distances from the flat plane of the table with the fan exhausting toward the ceiling. As I did this I kept my other hand at a given distance above the fan so that the only variable was the intake distance. I could really feel a decrease in static pressure once the distance between the table top and the fan became less than about 60% of the fan's diameter. It made me think how a lot of cheap cases have the front fan mount just behind the plastic bezel with only some small vents to the side or bottom. That's really going to starve the fan. Something to keep in mind when choosing cases and also fan configurations for positive case pressure.
So I down-clocked it and lowered the vcore considerably but it didn't help as much as I needed and now the lower clock speed dinged the performance to the point where I pulled the G3258 and put in an i3 4170 at stock voltage. That gave stress temps in the low 90s, just barely below Tjmax.
I was surprised because the Noctua NH-L9x65 is a fairly hefty hunk of metal for a low profile cooler. As I was looking the situation over I realized the problem was that there was only about 12 mm of space between the bottom of the PSU and the cooler fan. I took it all out of the case and bread boarded it and temps came way down. Did some research on how clearance to fan affects fan performance and discovered that the rule of thumb is that for an axial fan the clearance should be equal to the diameter of the fan. This Noctua cooler has a 92mm fan so that would equate to 46 mm. It's not hard to see that the fan was starved for air.
I can see that with this case the only good choice for cpu cooling is an AOI water so I ordered the Corsair H55 Quiet edition. Uncharacteristically, Amazon bungled the shipment routing and it was sent in the wrong direction so it might be a couple more days before I get it.
But just as an aside I did a little informal experiment with a 140 mm fan I had laying around. I connected it to a PSU and moved it up and down off a table top at various distances from the flat plane of the table with the fan exhausting toward the ceiling. As I did this I kept my other hand at a given distance above the fan so that the only variable was the intake distance. I could really feel a decrease in static pressure once the distance between the table top and the fan became less than about 60% of the fan's diameter. It made me think how a lot of cheap cases have the front fan mount just behind the plastic bezel with only some small vents to the side or bottom. That's really going to starve the fan. Something to keep in mind when choosing cases and also fan configurations for positive case pressure.
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