In my M700 Tiny I installed an M2 ssd as boot drive (Intel DC S3520), and a SATA mechanical drive for data (Toshiba 500GB 7200rpm). 

The ssd temperature is 65C and the hd temperature is 55C under very light load.

Are these normal temperatures for the model? With these numbers both drives will fail in no time.

I don't believe the OEM drives will fare differently: after all, there is no vent whatsoever (the only fan is for CPU).

Are the temps high across the board, what are the CPU temps at idle and under load?  Can you hear the fan running, and running harder under load?  What is the BIOS version?  Half the front cover is vented (and was avail with an optional dust shield, if equipped verify that it is clean, see Pg 78 of HMM), and the cooler vents heated air out the rear, under load, do you feel much air coming from the rear vent? 

The high temperature is limited to hard drives only. I just updated BIOS to the latest version. Same symptoms.

BIOS Version/Date    LENOVO FWKTB9A, 8/17/2021

                 cpu temp   fan    cpu% hd/ssd temp
handbrake   70            on    100    48/58
WMC           50         silent   8        52/61

The lower temperatures of 52/61 are probably due to the cooler room temperature in the morning. In the afternoon they will reach 55/65.

Cooler radiators of this type (located inside the rear grill) have a propensity to clog with dust.  Remove the fan, and clear the inside of the radiator.  ThinkCentre BIOS' often have a fan setting, better acoustics is the default, you could try the better thermal setting. 

The problem is not with the CPU fan: CPU is not overheating, and 50 degrees at idle is normal for tiny form factor.

Since I am using it as a media PC, the last thing I want is more fan noise.

Can somebody confirm that M700 Tiny idles with hd at 55 degrees. If this is true, the natural conclusion is that hd should never be used.

The CPU fan (the only fan) vents heated air out the rear of the small case, creating airflow, which cools the drives. 

Are you sure the hard drive has to be cooled by the CPU fan? Besides, the fan is already running even when the CPU idles.

The exact same Toshiba drive runs at 40 degrees in my T500 (no fan there). Additionally, I don't recollect M73 having the crazy number (55C) when it runs on a 500GB mechanical drive.

The CPU and M2 ssd are 4-5 degrees cooler after I remove the mechanical drive.

Can someone with a M700 or M900 Tiny, please post what their HDD and/or SSD temps are?  I would greatly appreciated it, ty. 

Hi BiggAl, thanks for answering my questions.

I did some more testing on idle temperatures, and here are the numbers with one drive installed on different models:
           T500   M73   M700
2.5" hd   40     50
2.5" ssd           45
M2 ssd                       60

An hd in M700 will raise temperature by 5 degrees, so hd is at 55C and M2 is at 65.
A 2.5" ssd in M700 probably will raise temperature by 2 or 3 degrees, I did not test.

Sadly I have to conclude that only one slot of 2.5" and M2 should be used in M700, not both.
Even with one drive, hd and M2 ssd are at the max of normal operation temperature range, 50 and 60, respectively.

That means the only acceptable configuration is one 2.5" ssd. The Tiny form factor is simply problematic.