I picked up 2 HGST He8 8TB drives for my EX2 Ultra. These drives run pretty cool unless transferring massive amounts of data & even then they don’t get to hot in a desktop environment.
I had a 6TB Red drive in it that would top out 43c & the fan was always on from boot-up. Usually ran in the lower 3000 RPM range. Installed the HGST He8’s in my EX2 Ultra. At first the fan on the Ultra wouldn’t turn on. Drives were getting to 50c while transferring files & no fan activity. I rebooted it a couple times & the fan turned on running around 4400 RPM. Then it spun up to 9000 RPM for a while.
Currently the drives are at 41c & 43c and the fan is running at 8333 RPM during a hour long data transfer. The fan has never ran this high.
I do not think any one has posted yet if the new firmware changed the fan set point and speed tables.
I do find it odd that blowing the hot air coming off the disk drives back to the mother board in a DL4100 makes the fan come on.At least UI Diagnostics health shows RPM.
May have to re post if I find my fan was turning the build in fan
We get temp of 57 C + when raid rebuilding so some users have external small USB fans for extra cooling. ( 39 C with an extra fan )
I found a 12 volt 65w power supply & started using that on my EX2 Ultra. The fan turns on now when both drives hit somewhere around 48c. Not sure what the cpu is at when it turns on.
Haven’t heard anything out of WD Support since last week.
I should add that people have used small 12 volt computer cooling fans on a USB-3 port BUT many time they will fail to start every time due to the lower voltage.
So far my unit only seem too hot when doing a raid rebuild and not normal operation.