In November 2020 I heard from Carl:
I recently bought a HP t630 to run as a small ESX host. Having a couple of 32GB DDR4 SODIMMs, I thought I would give them a go. (Crucial CT32G4SFD8266: DDR4, 2666 MHz, 260-Pin, 1.2 V, CL19)
With the 64GB installed ESX would not install, saying that it needed a minimum of 4GB to install. I took one SODIMM out and it installed ok with 32GB of RAM. Not wanting to give up, I put the SODIMM back to bring the installed memory up to 64GB. The system booted quite happily and ESX reported 62.96GB of usable RAM.
I have another t630 running with 48GB, 32GB & 16GB all with no issues.
It sounds to me that the installer has one of those size/boundary issues where 64GB has overflowed the 'memory size' field and is being reported as zero or a negative number.
In December 2021 I received an email from Emma also on the topic of running with 64GB of RAM.
I was setting up a t630 with 64GB of memory to use with Proxmox. The problem was that it was only showing 4GB of RAM! I figured out the reason, though: I had set the BIOS to force a 256M size for the video memory to try to minimize the "memory hole." It appears Linux doesn't care for that and skips all the memory after the forced buffer size. Once I set it back to auto, Proxmox could see 61.78GB of memory.
I don't fully understand what was going on there, but the message is plain. If a lot of your 64GB has gone AWOL playing with the BIOS setting for the video buffer size might bring it back.
Later In December 2021 I heard from Nick:
I'm using one with Windows 10 Professional and it works really well after a small upgrade. I added another stick of RAM to bring the total up to 8GB and swapped in a larger 250GB SATA M.2 SSD.
He's also enjoying the bonus of thin client hardware based solutions - total silence due to the absence of fans.
In May 2023 Rytis emailed:
I picked up a pair of HP T630 with 8GB memory and 128 GB M.2 SSD, licensed for Windows 10 Pro.
Upgrading to Win11 Pro works using the 'AllowUpgradesWithUnsupportedTPMOrCPU' registry hack to bypass the soft CPU incompatibility test failure. (It passes the other Win11 upgrade tests).
MX Linux 21.3 (Wildflower) kernel 6.x works out of the box, without having to install non-free firmware.
OPNSense 23.1 works out of the box (added a USB network adapter)
Debian 12 RC2 (bookworm) works out of the box without having to install non-free firmware, kernel 6.x
Open Media Vault 6.3.11 works out of the box, especially nice opportunity to use the the extra M.2 SSD slot, if one can find affordable storage for that. Storage hanging off of the USB 3 works fine with it, reasonably fast in my opinion although you need to watch the USB power budget if you are hanging a storage array without providing any external power for it.
Power utilization is 8 watts (Linux OS) with peaks of 16 watts with workload.
In March 2024 I heard from Mick
I put Windows 2022 Server Datacenter Edition onto a USB Stick and and installed it on the t630. The install went smoothly and 20 minutes later I had 2022 Server Datacenter (Graphical Experience) installed. This seems quite smooth on the t630, ticking along at 1% @ 0.88Ghz idle and using 1.6GB of 7.0Gb available RAM and 17.7Gb of 29.0Gb SSD.The only driver issue was the SMBus Controller. This didn't install automatically, so I downloaded the Windows 10 drivers from HP's site. This then caused a Firmware issue under Device Manager, which was resolved by just rolling back that driver to the previous version.