Discussion The role of a chassis fan in a plain, integrated graphics desktop for average use

[mikeymikec]

Soon after I started building computers for customers, I understood from what I read that hard drives benefited from a bit of ventilation, particularly if they're in a cramped case. Often the plain desktop cases came with a chassis fan so I thought why not just use them.

Since SSDs came into the mainstream I've been on the fence about adopting the same line of logic. Sure, SSDs don't like a great variation in temperature so the same argument still applies to some extent, but given that the desktop chassis (what's the plural of chassis? no idea) I use aren't cramped for space and also it's a rarity for the SSD to be pushed hard, does a chassis fan still have a purpose in such a scenario?

I've been a long-time user of ASUS boards and so I have used their fan management systems for almost as long as I've been in business, but recently I've changed up to using MSI for my plainer builds. I decided to try an experiment with the latest average build, spec:

AMD Ryzen 3 4300G, stock heatsink
8GB DDR4-3200 (with the memory profile enabled)
MSI B550M PRO VDH WIFI, latest BIOS
Samsung 970 Evo Plus 250GB (M.2, beneath the heatsink supplied with the board)
Fractal Design Core 1100 case
Be Quiet! System Power 10 450W PSU
Win11

To begin with, my concern was whether the custom fan profile (prioritised for reducing noise) for the chassis fan (at the front of the case) was set too low for the SSD to benefit, so the fan was running at about 500RPM at the time the test started. I brought the computer out of sleep mode (it had been in sleep overnight), and after a few minutes I set up the test: HWMonitor running and showing me the SSD sensor readings, and a recent-ish version of ATTO to bench the SSD. Post bench max readings were 48C, 48C and 59C.

After the test ran through I then resetted the profile and just enabled MSI's smart fan feature (which tripled the chassis fan speed), but the post bench readings were basically a degree higher or lower depending on which sensor. Obviously I didn't perform the test in the most perfectly scientific of ways, but if tripling the fan speed makes a negligible difference in a test that leans towards fans being good then is it really worth having.

Side note - I honestly don't think the SSD heatsink that comes with that board makes a noteworthy difference (those load temps are just where I would expect them to be and I've used that model SSD without a heatsink plenty of times), at least not with regard to gen3 M.2 speeds.

Obviously a chassis fan cools more than just the SSD but it seemed like an easy target for testing as well as a component that's easy to argue taking good care of.

Thoughts?

 

[Paperdoc]

Interesting info.

My own thought (beliefs? right or not!) is that the SSD is not one of the high-concern items for heat removal. I always thought of the North Bridge and VRM chips as big heat sources, as well as the CPU of course. If you are using an air cooler for the CPU, then I believe it vital to have good case ventilation to remove the heat inside the case. A liquid-cooled CPU system may be different there, but even with those you need good air FLOW through the rad, so case vent fans to assist the rad fans are important, I think.

 

[mikeymikec]

Interesting point. Admittedly in this case, the 12cm chassis fan is at the front of the case (and the rear grill can only take an 8cm or 9.2cm fan). There's also the PSU pulling air in from the top-left corner of the board.

I've always defaulted to boards that have VRM heatsinks in the belief/hope that those heatsinks are worth a damn. I've just had a trawl through the extra sensor readings I can pick up in psensor on Linux, but I don't see a sensor name that screams "VRM" to me. Does anyone know what one should look for if one wanted to test fan effectiveness wrt the VRM temps? Sure, I could slap a temperature sensor on the VRM HSF, if I had one

 

[Paperdoc]

In the mobo manual p. 60 the screen shot shows at top left six possible temperature sensors. My interpretation of their labels is that System is a general temp sensor on the mobo commonly used to guide case vent fans, Chipset is probably the North Bridge / South Bridge chip, and MOS is the Voltage Control section temp sensor. One component type in the Voltage Control system is a MOSFET - short for Metal Oxide Semiconductor Field Effect Transistor, a device that can control current flow in a circuit according to control signals, and can do so for heavier currents than most types of transistors. So those higher currents flowing through the internal resistance of the MOSFET junction can create significant waste heat.