[SOLVED] CPU fan port on MoBo erratic - does not work with certain fan when RAM is installed on board.

[Kudama]

I’m a noob to this forum and to builds. I am attempting my first build and have endless questions, many of which I’ve been able to find answers for. Here is one of the ones I cannot find an answer to anywhere.
I have a MasterCooler Hyper 212 Evo CPU cooler and I’m using a Thermal Take Riing 12 fan (the stock one rattles and grinds like crazy).
When I have the fan plugged into the CPU fan port and there is no RAM installed it works fine. When The RAM is installed it turns on when the system powers up, but turns off immediately.
When it’s plugged into a system fan port it works fine.
When the crappy stock fan for the Hyper 12 Evo is plugged into the CPU fan port it runs fine (if you like very loud rasping noise).
I cannot have a system with no RAM and I’ve read that one should not use a system fan port for a cpu cooler fan.
I have not installed an OS because I felt like I should resolve this before proceeding.

My questions are:
Does anyone have any idea why the presence of RAM disables the CPU fan port?
Does anyone have a workaround that they’ve used or heard of for similar issues?


I really wanted to work on this tonight and get it loaded with its OS and software for tomorrow so I’m hoping the answer isn’t “get a new fan”. (Like I said, the fan works fine in the sys fan port and it’s as quiet as a pleasant thought.)
Thanks! Moving forward, I will endeavor to contribute any knowledge I might have that could help others and balance the cosmic ledger.


Parts:
MoBO- MSI z590 Gaming Edge Wifi
CPU- Intel i9 10850
GPU- Zotac Geforce GTX 1660
Fans- three Thermal Take Riing 12 (including the CPU fan) and the two that were stock with the case
RAM- four Corsair Vengeance RGB Pro 16 Gb ;3200

 

[lvt]

Do you have a pair of other RAM modules to test?

 

[Paperdoc]

You MIGHT need to adjust one setting in BIOS Setup for the CPU_FAN header. See the mobo manual p. 40. It says the default MODE setting is "Auto" which should be OK, but maybe not. FIRST, look closely at the wires from that Riing 12 fan - there are several models with similar names but different designs. IF the connector for that fan has THREE holes in it, set the Mode for the port to DC (Mode is set at upper left of the graph page shown on the manual.) IF the fan connector has FOUR holes, set it to PWM. If you've made a change, use Esc back to Main Menu, then the F10 key to pop up an Exit Menu where you choose to Save Change and Reset.

Another thought. Check the routing of the fan's cable. Just in case some of its signals are interfering with the RAM modules, make sure it is routed away from those.

You have five fans in total of two designs, but I have assumed that the one you are concerned about (on the CPU cooler) is the ONLY fan plugged into the CPU_FAN header. This CAN be an issue if this fan is what's called an LED Fan. That is a type that has lights in the frame but only ONE cable to the fan. Then the lights are of one colour only and you have no way to alter them - they always come on when the fan has power. That type of fan uses more power than an unlighted fans but is NOT a problem for most fan headers. It MIGHT be part of a problem, though, if it is used with several other fans all on ONE header.

 

[Kudama]

Thank you both so much.
Here’s what happened: I don’t have any extra DDR4, but I would be able to cannibalize the Acer prebuilt that pushed me over the edge and drove me to this crazy path of betting over a thou on my complete lack of knowledge and experience being compensated for by Youtube.
I was prepared to gut my new $1,200 Acer solitaire and email machine but went the path of least resistance and powered back up. The fan connector has three prongs, so I set it from Auto to DC and it started up but died right away. I sat there and considered plugging it into the system fan port and just watching the cpu temp while I installed Windows. On a lark I changed the fan type to PWM, and it is still running. I don’t know if they follow weird manufacturing conventions or what, but your fix was right on target with the other setting.

I was going to go to bed but not now! For over a month I’ve been LITERALLY QUESTING!!! for this computer, back and forth across three counties physically, dealing in back parking lots for the last cpu cooler in California, and juggling countless+ internet packages jealously delivery-tracked and snatched away from porch pirates. Every crescendo of triumph has instantly become a trumpet blat. God has taken a personal hand in keeping this computer from me, ‘for real!
So… sincerely thanks again. Your help has made my night and morning. Now I’m waiting for the cosmic millipede to drop another shoe. It’s kind of become predictable at this point.


Pointless aside here, but…I really wanted to get to loading the OS and I have two slim profile Noctua fans coming on Tuesday and this Riing 12 one will be going to the rear case port. It presses pretty tightly into the closest RAM stick on one side and scrapes against the IO casing on the other- the tolerance is so tight that the (I think) -10mm will make all the difference. But! I just want to protect the cpu long enough to proceed in loading up the OS, drivers and all. I am uploading it with only one RAM stick in each channel to free up the fan space on that side and will add the additional sticks when the slim profiles come in. In this way I plan to develop a relationship of reward and denial with the machine, imagining that it will lap thirstily at the new memory and associate its pleasure with my user ID. Then I will consistently offer empty promises of more memory and never come through. I see it is late and my mind falters. I go now to contain a demon by its own lust for storage.
What could possibly go wrong?

 

[Paperdoc]

Glad to hear of your progress. Nervous about how you temp fates with your last sentence.

 

[Kudama]

I just realized.. .Do I have to do anything to mark this thread as "solved"?

I can't even tell yáll how happy I am to see my fan scampering.

 

[Paperdoc]

You do not have to do it, but certainly can if you wish. See this topic

Info - How to Award Best Answers/Mark question as solved

This post is replaced with - https://forums.tomshardware.com/threads/how-to-mark-posts-as-solved-award-best-answer.3803582/ The means by which a Best Answer is awarded has changed since we moved from old forums to this brave new world. If you are the thread opener, you have a choice in the...

forums.tomshardware.com

It appears that awarding a Best Solution is the route for declaring a thread Solved.