CPU Scythe Kaze Flex 120 Black vs Noctua A12x25 & A12x15 on Alpenfoehn Blackridge Air Cooler

Mark13

Cable-Tie Ninja
Original poster
Sep 5, 2020
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Last Sunday I posted my comparison of the new Scythe Kaze Flex 120 - 1500 RPM Black fan when mounted on a Noctua L12 Ghost Edition as the top fan on a dual fan down draft small form factor build. For this new dual downdraft comparison, I used an Alpenfoehn Blackridge cooler with a Noctua A9x14 fan under the cooler on an Aorus B550 ITX MB with a 4750G APU build with 32GB Ram in a 5.9 liter Yiluka YLK-01 case with no space for other fans - exactly the same setup except for the cooler & bottom fan. I ran the Blender classroom render and Unigine Valley at the same time to stress the entire CPU/GPU of the processor. The highest temperatures in CPUID HWMonitor were noted after completing the 10 minute render.
I was curious if the denser fin array of the Blackridge cooler would improve the A12x25 fan performance versus the Kaze Flex Black - CPU was 1 degree cooler, the other temps swap back & forth between the two thicker fans in this comparison. The A9x14 fan has a distinct whine between 1600-2500 RPM that the A9x25 fan does not have up to its 2000 RPM max rotation. The other dual fan L12 GE cooler combination was several degrees cooler on all temperature sensors with each of the 3 fans. The L12 GE with a 25mm fan is 91mm in cooler height. The Blackridge cooler with the A12x15 fan fits nicely in a Lazer LZ7 or 678 case with their approximately 70mm cooler height limit. The Blackridge cooler will not fit on a number of ITX motherboards - the Aorus X570 in particular . You also need to purchase and use the NM-AM4-L9aL9i Backplate to obtain proper cooler mounting pressure. Both fans had individual MB fan headers & were set to read the CPU temp & could rotate up to their max speed. Below are actual temps in a 21C room:

Top Fan​
Noctua
A12x25​
Kaze Flex 120 Black​
Noctua
A12x15​
Temp Sensor 0​
46​
44​
47​
Temp Sensor 1​
47​
47​
49​
Temp Sensor 2 CPU​
75​
76​
77​
Temp Sensor 3 PCI​
21​
21​
21​
Temp Sensor 4​
46​
47​
48​
Temp Sensor 5​
47​
46​
49​
Pkg Temp​
75​
76​
78​
Wattage​
89.04​
89.17​
89.06​
NVMe Top​
48​
48​
50​
NVMe Bottom​
42​
42​
44​
Render Time​
/ 10:24.73​
/ 10:23.44​
/ 10:27.15​