I have just built a new server PC using the Lian Li PC-Q27B chassis and would like to share some experiences. Particularly regarding what fans to use, and what positioning of those results in the best and most quiet cooling.
Some illustrations:
(Note: The pictures are not my own, but shows quite good what the case looks like)
1. The build consists of:
* Lian-Li PC-Q27B chassis
* Asus H87I-plus Mini-ITX motherboard
* Seasonic G-360 PSU
* Scythe Big Shuriken Rev B CPU cooler
* Intel Core i5-4440 CPU
* 8 GB RAM
* 1x2.5" 80 GB Intel SSD
* 2x3.5" 6 TB WD Red HDD
* 1x5.25" DVD-R
2. Basic chassis impression: Very small and nicely designed. Noticeably smaller than e.g. the similar Lian Li PC-Q08 or PC-Q11B. Reasonably easy to build given the size. Very clever mounting of the side panels - only requires one screw to mount/unmount. The PSU can be mounted in two directions, i.e. either the PSU fan faces the chassis wall or the CPU. The included HDD mounting grommets help reduce HDD vibration noise.
3. Fan cooling experimenting: This chassis has a design which is very similar to several other Lian-Li Mini-ITX chassis-es. More precisely the PSU and CPU cooler/fan is placed at the top of the chassis, facing each other. Since the space between those is small, it immediately leads to the question what CPU cooler to choose and in what direction the CPU cooler and PSU fans should be facing. Is it e.g. more efficient to let the PSU fan face the chassis wall so it does not compete with air from the CPU cooler fan? And should the CPU fan be blowing towards the motherboard into the PSU?
Since there are no obvious answers I did some experimenting. I waited until the computer was idle, then started Orthos Prime 95 torture test (Small FFTs) on all 4 cores to maximize CPU heat dissipation, and measured the CPU temperature over time. Ambient temp was 22 degrees C on all occasions. The temperatures specified is that of the hottest CPU core (the other cores were usually max 4 degrees below that). Some tests were aborted early, because the temperature rose above around 90C.
See results below:
A)
Fan: Scythe Big Shuriken Rev B included fan, 12 mm height, PWM controlled, max 2000 RPM. CPU fan blowing towards motherboard. PSU facing CPU fan, i.e. sucking in air from that direction, "competing" for air with the CPU fan.
Idle: 30C
15 min: 84C
60 min: 88C
B)
Same as A), but CPU fan blowing towards PSU:
Idle: 30C
15 min: 80C
30 min: 83C
C)
Same as A), but PSU fan facing chassis wall.
Idle: 32C
5 min: 81C
15 min: 86C
30 min: 89C
D)
Fan: Scythe Gentle Typhoon, 25 mm height, fixed 800 RPM. CPU fan blowing towards motherboard. PSU fan facing CPU fan.
Idle: 37C
2 min: 93C
E)
Same as D), but PSU fan facing chassis wall.
Idle: 30C
3 min: 91C
F)
Fan: Noctua NF-F12, 25 mm height, PWM controlled, max 1500 RPM. CPU fan blowing towards PSU. PSU fan facing CPU fan.
Idle: 29C
5 min: 71C
15 min: 75C
60 min: 77C
Conclusion: In short, F) was clearly the most efficient cooling solution. In addition, it was also the one that was the most quiet one. I do not have any sound level measurement equipment, but it was easily noticed by just plain listening. D&E) were about as quiet as F), but since it's cooling efficiency was so poor due to max 800 RPM of that fan it was not really an option.
Using the solution in F), hot air from the CPU is blown into the PSU, and then effectively transported out of the chassis. I think this is the reason it was the best option. Also, the Noctua NF-F12 fan used in F) has a high static pressure, so it is able to blow air through passages with high resistance. I think that makes the fan well suited in this case.
Please let me know what you think and if you have any questions!