Introduction to the HP t640 Thin client - your cheap little AMD NUC7 alternative

Welcome to the short and succint guide to the HP t640 thin client

(Also known by HP internal codename Tranquill)

So why should you care (as a home labber)?

It's a small-ish thin client, roughly 196mm W x 196mm H x 35 mm D , ~1.35 Liters, released Q3 2019, general availability in Q2 2020.

The HP t-series thin clients are about as close as AMD got to releasing an intel NUC competitor.

In the t640, you have a Ryzen embedded R1505G APU within the AMD Banded Kestrel family, which offers decent performance, low power usage/noise levels and a useable embedded GPU (Vega 3). It’s nearest equivalent is the AMD Athlon Gold 3150e. It can also be had with a rather attractive price of about 175-200 USD used in the secondary market stateside, which compares very well with Coffee Lake NUCs/corporate NUCs available. It dipped as low as 100 USD back in Q1 ‘21.

How much CPU and GPU firepower can I expect from one?

The Ryzen R1505G has a CPU configuration of 2 cores, 2 threads on a 14nm lithography process (it’s Zen and not Zen+). The performance is comparable to the AMD Athlon 300U or the Kaby Lake-U i7-7560U. System TDP is at a noteworthy 15w, passively cooled via convection.

The Radeon Vega 3 embedded GPU onboard has 3 Vega Compute Units arranged in a 192 Unified Shader: 12 Render Output Unit:4 Texture Mapper Unit configuration. Raw GPU horsepower is about 384 Gigaflops, roughly 25% of a PS4.

Base configuration as shipped is 4GB of RAM in 2 DDR4 DIMMs, and 16GB of eMMC in the M.2 slot using SD7 (SD storage via PCIe interconnect) - the first example being the Sandisk Mothim cards.

Base OS is HP ThinPro (a variant of Ubuntu Linux) or Windows 10 IoT edition x64.

What’s my path to expandability?

• 2 DDR4 Notebook RAM slots - officially supporting up 32 GB via a pair of 16GB DDR4 DIMMs, but 64GB (via a pair of 32GB SODIMMs) will also work.

ECC Support?

• Not supported. Tried it with a pair of DDR4-2933 8GB SODIMMs. No support for it whatsoever AFAIK, at least not on my unit for BIOS 1.06.

• 2 M.2 slot -
- Key E (Wireless, HP/Allied Telesis AT27/29 M2 fiber NIC or PCIe x1)
- HP FlexIO for the option port (note that this is specific for the thin tx4x client line and not compatible with the EliteDesk line)
- Key B+M (SATA or NVMe)
- Sandisk Mothim SD7 cards

• 2 USB3.1 ports in the back, 2 USB 2.0 ports (at an angle in the back), 2 USB 3.1 ports in the front, one USB 3.1 type C port in an option bay out back.
• USB 3.1 Gen 2 with power distribution is an option (L42726-000) on the breakout port, as is a serial port (L42732-000) and the micro display port (L42434-000). Note that USB-PD requires a 10 pin cable from HP that is not that easy to second source.

Upgrade Compatibility with the t630/730
  • RAM: Yes for the t630 - the t640 requires DDR4 - the t630 is DDR4. The t620/730 is DDR3 and will not work
  • M.2 (SATA or NVMe): Works fine
  • m.2 Key A+E slot - the old fiber cards should fit, and as for the Wifi....you'll need to figure out how to run the antennas if it's not included in your particular SKU
Is there a guide to working inside the chassis?

HP has a policy of providing teardown/e-cycling guide for their hardware, and this is the one for the t640 (it's a PDF file). Note that the teardown guide always reference the product codename and it looks like the factory assembly procedure but in reverse.

OS Compatibility with the t640

The following bas been tested and known to work:

Windows 10 IoT/Pro, Windows 11
Debian Linux 10 to 12

How much am I expected to pay for one?

As of Q4 2023, about 65-110 USD for a refurb unit - they are being pushed out by the HP t655 Elite series replacements.

  • More performant than the t630 or t730, and competitive against a NUCi5/7th Gen Core model (do keep in mind that this APU has a 15w max TDP so you can't compare it against CPUs with double or triple its margin).
  • Three DisplayPorts coupled with an okay decent Vega 3 GPU
  • About 3% smaller than a 2019 Mac Mini (1.34L versus 1.37 L)
  • Passively cooled/fanless
  • M.2 SATA/NVMe upgradeability (and SD7 as well)
  • M.2 Key A+E PCIe slot can be used for wireless/fiber networking
  • The AT29M2-SC001 fiber NIC from the t630/730 can be re-used

• No IPMI, and no VPro (AMD DASH seem to be limited to Windows OS only)
• Only 2 DDR4 Notebook DIMM slots (64GB is the max, so about the same as the Intel 8th Gen NUCs)
• If upgrading from a t620 Plus/t630, it needs a 45w HP power brick, HP 7.0x4.5mm blue-ring-tip Notebook power plug. Those with the USB-PD option port can run it off USB-C power injection though.
• The default NIC is a Realtek GigE model, and they are known until recently for some truly crapulent showstopping drivers (also, no native ESXi driver, so no driver support for VSphere 7+)
• No PCIe slot (so it preludes quite a number of uses)
• The fiber NIC option based on a Broadcom Tigon, which also does not have native ESXi drivers - also no driver support for VSphere 7.
• The Vega 3 is a GCN5/VCN1 design (Navi/RDNA is not available until after the Renoir APUs). If you plan to use it as an HTPC box, it'll decode H264/H265 (HEVC) up to 4k, and VP9 is only assisted decoding. H264/H265 encoding is...not great compared to Intel Quicksync. AV1 encoding/decoding are not supported.

So, what can I do with it?

- Use it as a thin client.
You can drive up to 3 LCDs in 4k resolution (well, 4, if the option port has a miniDP or VGA breakout), so at the very least you can use Synergy to connect to multiple desktops. HP ThinPro out of the box can support various protocols like VNC, RDP, VNC RGS, NoMachine NX, AWS or Cendio ThinLinc. USB remote access is supported so you can in theory setup a remote VM in KVM and remotely connect USB and audio to it via the SPICE protocol.

So yes. Use it to drive multiple screens - delight friends, intimidate enemies.

- Run a “more powerful” firewall (as long as it’s gigabit and only require 2 ports (one of which is fiber based port ), or if you like the idea of USB3 based NICs).

The default port is a Realtek 8111, and the optional AT29M2 is Broadcom, Gigabit and duplex fiber based. There are USB 3.1 Gen2 ports for nBaseT networking, but that’s rather expensive.

- Low-medium performance expandable hypervisor.

Yeah, it’s more powerful than the RX427BB of the outgoing t730, and SVM/RVI/AMDV-i is enabled. As long as you are comfortable with only 2 GigE ports in total, you could in theory load up a few VMs (with 32 to 64GB of RAM) and do some useful stuff with it. That being said, one M.2 NVMe card and potential Gigabit iSCSI is not your avenue to mind-blowing performance. ESXi 6+ is generally not recommended due to lack of native driver support for the Realtek NIC.

- Use it as an HTPC or as a living room PC.

It's very slightly smaller than the 2019 Mac mini, but you get expandable RAM (2 DDR4 SODIMM slots), storage (a single m.2 slot) and Gigabit fiber/wireless+bluetooh connectivity. It can play h264/h265/VP9 and any older format just fine. Not sure if Plex will allow you to do transcoding via AMD VCE/VCN support, though.

- You can do some light gaming on it

Expect it to perform like an AMD Athlon 200U in gaming.

Are there similar products out in the market today?

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Great overview of the T640
Yeah, my intention is to add these guides for the entire AMD flexible thin client line (t620/t620 Plus, t630, t640 and t740). Considering how many people are hacking the t620 Plus to be firewalls and stuff, we might as well host an authoritative guide for them.