Do I need to cool this WD HDD?

Good point, I hadn't mentioned that. The temperatures are measured with Hard Disc Sentinel, Speccy gives the same values.

Those temps you list in your 1st reply are way too high.

My Samsung 860 Pro runs at 26 to 28C

The hard drive cage in my Corsair C70 case has a fan pushing and 1 pulling on either side.

Ordered a Noctua NF-A9 92mm yesterday, it's just been delivered. I have a few things to do this today so I'll see about taking time out to fit it tomorrow (with my wife's permission of course), also see about moving the WD HDD further from the RAM.

The PC, still with the side panel removed, has been on for about 7 hours, the HDD is running at 42C, much more satisfactory.

Thank you, as ever I've learned a lot from these exchanges.

I always bought HDD box to keep HDD running cool and quiet.
There are a bit hard to get these days, since everyone uses SSD.

Scythe Himuro Hard Disk Cooler | Introduction | Storage | OC3D Review

An update to the thread.

I fitted the NF-A9 yesterday. Bit of trouble getting the silicon mounts to engage with the drive, had to remove the PSU to get to one of them, but got it fitted eventually. As the lead wasn't quite long enough to reach any of the FAN headers, I chose to use the Low Noise Adapter as an extension and connected it to 4-pin SYS_FAN2. I also investigated moving the HDD away from the RAM; unfortunately though I could have put it lower down it would then only have been supported on one side. I was able however to move it a little further forward in the tray, so now it's perhaps 1-1.5cm further from the RAM.

Powered up the PC, saw the fan spin as soon as power supplied, then it stopped immediately after the short single POST beep. Odd?

Checked BIOS settings, all ok. After a bit of head scratching connected it to 3-pin SYS_FAN1. Worked perfectly.

Replaced all panels and let it run for a few hours. Temperature stabilised at 42C.

Then decided to use the normal extension lead and thus let the fan run at full speed. after a few hours the temperature stabilised at 41C, little difference.

Clearly a vast improvement on the 50-52C previously. No idea why it stopped after POST on SYS_FAN2, not really an issue though, more a curiosity.

Clearly with more investment I could get the temperature down a bit more, but laws of diminishing returns set in at some stage. Have to be realistic and say that after 10 years how much longer will it continue to provide all I need?

tpriest said:

An update to the thread.

I fitted the NF-A9 yesterday. Bit of trouble getting the silicon mounts to engage with the drive, had to remove the PSU to get to one of them, but got it fitted eventually. As the lead wasn't quite long enough to reach any of the FAN headers, I chose to use the Low Noise Adapter as an extension and connected it to 4-pin SYS_FAN2. I also investigated moving the HDD away from the RAM; unfortunately though I could have put it lower down it would then only have been supported on one side. I was able however to move it a little further forward in the tray, so now it's perhaps 1-1.5cm further from the RAM.

Powered up the PC, saw the fan spin as soon as power supplied, then it stopped immediately after the short single POST beep. Odd?

Checked BIOS settings, all ok. After a bit of head scratching connected it to 3-pin SYS_FAN1. Worked perfectly.

Replaced all panels and let it run for a few hours. Temperature stabilised at 42C.

Then decided to use the normal extension lead and thus let the fan run at full speed. after a few hours the temperature stabilised at 41C, little difference.

Clearly a vast improvement on the 50-52C previously. No idea why it stopped after POST on SYS_FAN2, not really an issue though, more a curiosity.

Clearly with more investment I could get the temperature down a bit more, but laws of diminishing returns set in at some stage. Have to be realistic and say that after 10 years how much longer will it continue to provide all I need?

Save up your shekels, and get one of these...

Fractal Design Define R6 USB-C ATX Mid Tower Case (FD-CA-DEF-R6C-BK-TGL) - PCPartPicker

Apart from CPU fan there are no other fan speed controls in the BIOS.
Be that as it may, I'm happy with the outcome, the HDD is regularly 10-12°C below its previous temperature.

As always, thank you to all who've helped and cajoled me.