I spec and assemble components for a fanless, server-grade home computer, using the technology available in 2024. The technology will likely be relevant for a few years beyond that.
motivation
Off-the-shelf retail computer systems that are aimed at being competitive in performance are often built with cooling fans, in order to run CPUs at TDP levels that would otherwise not be possible. Fans, however, turn the box into an air filter, with dust that is present in the home catching on fan blades, heat sink fins, and electrical components. There are fanless designs, but these seem to assume that performance isn't important, and specifically that the system isn't going to be used in a server role, where 24×7 use demands ECC support at the motherboard level.
I'll also want 10GbE port capability at some point, since my ISP will soon be providing 10Gb service.
components
To fill the gap in the off-the-shelf offerings, I assembled the following system from these components:
| component | price |
|---|---|
| Intel Core i9-14900T processor | $650 |
| Supermicro X13SAZ-F motherboard | $600 |
| Streacom FC9 V2 case, HT4 riser, Nano160 PSU | $560 |
| 2 × Crucial MTC20C2085S1EC56BR 32GB ECC DDR5-5600 UDIMM | $325 |
These 2024 prices are in USD, approximate, with shipping and California taxes.
The FC9 provides up to 87W of conductive cooling via heat pipes to its external wall. The low-power “T” variant of the CPU produces 35W base TDP and up to 106W. The motherboard only provides two 1GbE ports, but both the case and motherboard support the ability to add a 10GbE PCI card later.
Intel low-power CPUs
The “T” variant of the Intel CPUs are difficult to find. I bought mine from Quiet PC Ltd. in the UK. Intel only sells them to OEMs, and those in the U.S. are generally large companies, like Dell, that are only interested in selling complete systems, not in selling components to hobbyists.
But the low-power variant is technically required: The X13SAZ-F motherboard only supports a TDP up to 125W. The FC9 case only supports a TDP of 87W. I have read opinions that the vanilla Intel CPUs can be tuned to have the same characteristics as the “T” variant, but it requires a level of settings fiddling and undervolting that I'm not comfortable attempting and that would take too much time to learn.
I would have preferred to buy the i9-13900T, since its specs are about the same and it should cost about $120 less, but I was unable to find any after Quiet PC Ltd. recently ran out of stock.
power supply
The CPU power supply (JPV1) is an 8-pin socket capable of supplying 360W of power to the motherboard, particularly when the 24-pin JPW1 is not being used. The Nano160 PSU, however, only has a 4-pin plug for this socket, which is only physically capable of supplying 180W, and which is further limited by the 160W maximum of the PSU. Since the CPU power usage should not exceed about 106W, these limitations should be OK. The 4-pin plug simply fills only half of the 8-pin socket.
assembly
tools
Assembly is straightforward, requiring only a Phillips screwdriver and thermal paste. A screwdriver for delicate applications, one with a narrow shaft, is preferred over one for heavier usage, so that it doesn't scratch the case. A 5mm wrench for lightly tightening the standoffs, and a 10mm wrench for tightening the PSU socket to the case, are useful. A headband magnifier is advisable, for inspecting the tiny pins of the CPU or RAM.
The FC9 and HT4 each come with some of Streacom's thermal paste—which I did use for the IHS-HT4 interface—but I think you'll find that the total amount that they give you is difficult to stretch. The heat pipes have some irregularities and the HT4 Upper Mount has some texture that you'll want to fill.
user guides
Assembling the system requires reading the Streacom FC9 and HT4, and the X13SAZ-F motherboard manuals, all of which are online, not packaged with the components. Intel has a reassuring video on LGA 1700 installation that you should watch, too. When installing the CPU or RAM, check for dust on the contacts, and blow it away if present.
PSU
Contrary to the FC9 documentation, the PSU needs to be installed before the CPU heatsink, because it sits below the heat pipes on this motherboard layout. The 4-pin PSU plug can only fit into the half of JPV1 nearest JPW1. Bend the black and yellow loops of wire of the 4-pin plug, as shown below, so that they avoid the heat pipes above them; the longer black and yellow wires that lead to the plug can be positioned between the PSU and the RAM. Also attach the disk drive extension to the PSU card at this point.
CPU cooler
positioning
Because the CPU on this motherboard is located closer to the front of the case than usual for Streacom's design, Streacom advises a non-standard configuration of the heat pipes that allow one of the longer pipes to fit but allows for only three pipes in total. Since I'm using the HT4 riser, however, I'm able to utilize all four pipes in a configuration that has one of the longer pipes inverted, lower, and pointing towards the rear of the case instead of the front. Using the heat pipe numbering in the FC9 manual:
- short, straight
- short, bent
- long, bent
- long, straight
I instead order the pipes: ①, ②, ④, ③, with ③ being inverted.
Note that the vertical pipes on the HT4 are positioned towards the side that the FC9 heat pipes are on. Streacom recommends this so that there is more proximity and contact between the sets of pipes. This does place the HT4 pipes closer to the RAM chips, but there seems to be adequate space between them.
You'll also notice that the SH2 heat pipes only overlap the HT4 ones by half the possible length. Streacom thinks this is adequate. There is a LH4 set of longer heat pipes that you could use instead for more overlap if you feel this is necessary.
Once the cooler is assembled as shown above to test the positioning, ensure that all the screws on the cooler are tightened:
- the three on the Heatsink Connector Blocks,
- the four on the HT4 Lower Mount, especially paying attention that the Adjustable Arms are immovable, and
- the four Spring Loaded Screws.
We'll leave the HT4 Upper Mount off for now. Lower the drive rack, to ensure that its edge fits between the heat pipes! (See the photo below.)
One thing to note about the inverted pipe: The heat pipes are copper tubes filled with some water in a vacuum. Ideally, the cooling end (the one against the case) should be elevated, so that the water can condense and flow back to the CPU. In the inverted pipe, the water will instead tend to pool at the cooling end, so it won't be available to aid in the heat transfer. Still, the copper of the pipe will provide some conduction, so it's better than not using it.
other approaches
Do not cut the heat pipes. The idea crossed my mind as a way of shortening the ones pointing towards the front; but doing so would ruin their effectiveness. Maybe bending the ends would be possible, but you're on your own there. I'd be afraid that heating the copper enough to bend it easily could cause the water to explode it.
thermal paste
As mentioned above, the Streacom TX13 paste works fine in the IHS-HT4 interface, because there's no need to spread it: just apply a reasonable amount and squish. For the heat pipes, though, I chose ProlimaTech PK-2: it has properties like TX13, but comes in a larger size, in a tube that dispenses more easily. It's electrically non-conductive and only slightly more fluid, so it doesn't run on vertical surfaces like the case wall. The viscosity of the paste also seems to correlate with thermal conductivity, another desirable property. I also don't buy the “reduced waste” greenwashing of the TX13 product when it takes 20 of their little 0.25g packets to match one 5g tube of PK-2.
- Remove the four Spring Loaded Screws, and the HT4 component. Apply some TX13 to the IHS (as directed in the HT4 manual). Secure the HT4 again in its previous position with the Spring Loaded Screws.
-
For each Heatsink Connector Block in turn, starting low and working upwards:
- Remove the pipe(s).
- Apply thermal paste to (a) the extent of the HT4 pipe(s) that make contact with the SH2 pipe(s), and (b) both sides of the SH2 pipe(s) that will be under the Heatsink Connector Block.
- Reattach the Heatsink Connector Block.
- Apply thermal paste to the tops of the SH2 pipes where they'll be covered by the HT4 Upper Mount. Reattach the HT4 Upper Mount.
tolerances
There is very little space between the heat pipe and the Nano160 PSU board.
When the disk rack is lowered into place, there is around a millimeter gap between it and the HT4.
The rack drops very fortunately between the heat pipes. Ensure that this happens intentionally for you! It was accidental in my case. It even shaved a little copper off the pipe as I lowered it. The rack edge makes contact with that heat pipe, for a little extra cooling, I guess.
The rack presses against the USB port cable. It digs in a little, but nothing of concern.
All in all, a very fortunate occurence.
next steps
I followed this up by running Memtest86+, just to test that the memory works and to perform a basic test on the CPU and motherboard. The maximum CPU temperature during the test was 43℃; most of the heat seemed to be coming from the memory chips. I'll need to install disks, and install Debian Linux, testing the disks for errors.
But after that, I'll want to run performance tests on the system, to see that it actually stays cool and fast at the same time. This will probably include capping the maximum sustained heat output of the CPU by setting the PL2 in the BIOS settings to 87W. Stay tuned for that blog post.
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