Scythe Ninja, which way should I set it to blow

[Dancer]

My question is should the fan be set to suck air from outside the case over the heatsink and RAM OR should it be set to suck air from inside the case from above the RAM over the heatsink and out the back.

Which is better for CPU and overall system temps. There are of course other considerations such as the PSU, read on for full details on the system.

I've got a Scythe Ninja Plus Rev. B with a 120mm fan that sucks air over the truly massive heatsink. I have a medium tower case with the Hiper HPU-4M580 PSU sucking in air for itself above it (most of it going out the back, but there are holes in the PSU case so some probably circulates back into the case).

Below the scythe, but with good separation, is the motherboard's (MSI P965 Platinum Intel P965) heatsink and below that the Gfx as usual.

On the right side are the driver bays. The SATAII HDs (2) are well below the heatsink and so well out of the way, the DVD drives are well above, so its really plenty of space on this side, although it's also of course where the RAM is. On the left side are big ventilator holes in the case.

Very crude diagram to illustrate airflow. Arrows show airflow, it's not as much space between PSU and Scythe as shown. More like a few centimeters or 1-2 inches. (ignore the dots)

back ______________front
..<-..|PSU]...............|
.......|../\.................|
.......|...|.................|
<->?|.[Scythe] [RAM]|
.......|.....[HEATSINK].|
.......|......................|
.......|.[GFX].............|
.......|.[PCI, etc.]......|
........-----------------

 

[SiriusB]

BACK---------------------------FRONT

<-- Outtake <---- Ninja <---- Intake <--

As you can see from my diagram the best setup is to have air sucked in at the front of the case, which blows towards the Ninja. The fan on the Ninja should blow the air through the heatsink towards the rear of the case where the hot air is expelled out the back.

This ensures a constant stream of cool air is brought in to cool the CPU and any warm air is quickly removed.

 

[Dancer]

Yes that seems an obvious solution, but that is not really an option. There's no space for air to get in at the front of the case, only a medium-to-small sized grill towards the bottom on the front. In contrast there are two large holed grills at the back just behind where the CPU is.

 

[SiriusB]

The cooling should be fine without the front intake. As long as any warm air from the Ninja gets pushed out the back of the case

 

[Dancer]

Ok, cool thanks I'll try that. There is a front intake, just not ideally situated or very big. It's truly a massive cooler... I like it

Of course the fan mounted that way blocks one dimm slot, but it doesn't matter as I only need 2 of the four slots anyway.

I quite like this motherboard as well, probably for another thread, but I just wanted to mention it. Has all the extras you would expect and a few that usually only come with more expensive cards like firewire and two GPU slots. Lots of cables and goodies too like both a rear USB panel and rear USB firewire for extra ports (the inbuilt panel already has x4 and x1 of those) and a nice large glossy foldout diagram with all the important bits labeled you could almost hang on the wall.