Premium Build: Greyscale — building a custom-looped ITX PC that pushes the form factor to its limits

When I was brainstorming build ideas for this second Showstopper at Tom’s Hardware Premium, the idea of pushing Mini-ITX to its absolute limit felt like more of a gag than something that could actually turn into a viable machine. In that respect, this build was more of a test to figure out “is it possible?” than actual buying advice. We aim to provide unique content, and hopefully this is what you came here for.

My thought was, nobody in their right mind would try to build this PC – to most, whether it would work is far too much of a gamble. However, that’s also what makes it such an interesting test.

Of course, I knew this wasn’t going to be a custom loop that runs cool and quiet; that much was obvious. What I didn’t expect, however, was that by accepting that it’d run hot, but not overheating under real-life workloads, that I’d still be able to get it to run relatively quietly, and that it’d actually turn into a perfectly pleasant PC for everyday use.

Truly: under gaming workloads with GPU and CPU temperatures hovering between 65°C and 85°C, noise levels hover between 34 and 35 dBA, with fan speeds of around 800-1300 RPM, all while not having touched power targets. If I may pat myself on the back, that’s downright impressive if you consider that in this little box we packed not only a 9950X3D, but also a beefy RTX 5090. With that in mind, the glass panel really is the cherry on the cake.

So, this is actually totally viable on any hardware, but how difficult is it?

If you’re truly interested in building a PC like this, I’d say that the biggest factor that affects the difficulty level is one’s state of mind. You have to be prepared for whatever it throws at you – whether a fan doesn’t fit, or you find a leak in the trickiest corner to get to – your mindset, the ability to accept that something isn’t going according to plan, and adapting, is the key to a successful build like this while enjoying the process.

In a way, that’s something that goes for any PC build – you have to be able to see the humor in preparing for the worst, and the worst then still happening. Laugh about it, enjoy fixing it, and carry on. Brutal acceptance is the only way, and better to laugh about it than to cry about it.

There are two more factors, though – you need small hands, that one doesn’t need a lot of explanation, and you need to be a bit creatively fearless.

If it can’t be done how it should, then it shall be done how it can

Not fearless in the careless kind of way – that will get you in trouble, but fearless in the ‘trust the process’ way. For example, let's talk about the fittings and tubing for a moment.

I had chosen to use this matt-black tubing, in the second-thickest size, because I like the chunky look and velvety finish. Let’s just say, that was a choice. It may technically be soft-tubing, but this stuff is rigid.

Consequently, when you try to get it around the tight bends needed in this build, the forces you have to put on some of the build are not for the faint of heart. In fact, you’ll often need angled adapters to make most of the bend you’re trying to make, using the soft-tubing to bridge the mostly straight distance between the compression fittings.

Getting the tubing onto the fittings isn’t that bad though. What’s tough is the force needed to twist the caps onto the fittings. I can’t stress how much force it took to get those to tighten up. Now, I am someone who’s prone to joint pain, especially when working on small detailed projects such as these, but I have to be real: the force that some of these took to tighten up was nothing short of huge.

If you have the tubing come in straight, with very little lateral pull on it, then it’s perfectly doable. But the moment you cut the end of the tubing at a slight angle, because you practically need to make part of the turn inside the fitting due to the rigidity of the tubing, they become incredibly tough to close.

It’s not recommended to work this way, you’re better off grabbing extra angled fittings, but this build had many elements of “if it can’t be done how it should, then it shall be done how it can.” Even moreso when it’s in the tight spaces of this build here. This was manageable at the start, but especially the corner pictured above, it was a real fight to get most of those fittings tightened up.

There were moments when I thought about getting out the pliers, simply because forces I needed to exert with my fingers became too painful. However, there were two problems with this – if my hands barely fit, getting pliers in there would be even more difficult, and even if possible, I didn’t want to scratch up the fitting caps.

The effort isn’t without its reward

However, what do you get in exchange? This PC is absolutely watertight, I have zero doubts about that. The fittings screwed into the blocks and radiators nicely with a clear “this is far enough, thank you” signal. And because they’re so incredibly strong, although tough to install, especially in the tight spaces, together with the rest of the components, have made the system so tough and rigid, I would almost classify this as rugged – if it wasn’t for the glass panel and the beautiful finish of the outside of the case. This is a PC you could confidently chuck in a suitcase and take on a flight, only removing most of the coolant so that it can deal with the pressure changes.

The level of confidence I have that this is a loop that won’t be developing any leaks, and can deal with a bump without it being cause for concern – this is truly wonderful.

With a 9950x3D, an RTX 5090, plenty of power and just the right amount of cooling capacity to still run quietly despite its form factor, this PC is ready to take on pretty much anything you could throw at it.

This was a tough build.