SFF build will not cost you more, unless you custom watercool it. Custom watercooling is only necessary if you're going for a super optimized build.

SFF cases are around $250-300, which is $150-200 more than a similar-quality ATX case. SFF CPU coolers are around the same price. SFF PSUs and motherboards have a small markup over ATX.

For example, here's a build for $3600. The GPU is not watercooled, though, since you can't fit a second radiator into the NZXT H1. https://pcpartpicker.com/list/Cr8cJb. This build has specs equivalent to the Corsair One a100, which retails for $4000. The H1 build also has a better upgrability path. Also, the 2080 Ti's price is massively inflated right now because of Ampere's imminent launch -- this build should really be only $3000.

You could also look into the Ncase M1 if you want to watercool the GPU, but I won't create a build for that because you would have to research hardware compatibility.

So it's completely feasible to build an SFF computer for less than what Corsair charges.

I’m running a 9900K and a 2080ti in a Ghost S1 with a few top hats custom loop and 2 240 rads, the Corsair isn’t a worse deal at that point.

That build cost quite a bit more than a Corsair One at similar specs.

It’s possible to build an SFF build for cheaper, it will be very hard to do so for the same spec as the One.

I didn’t know that the prebuilt market had gotten so competitive. Only a $400 premium to build, water cool, and warranty the damn thing? It’s a bargain.

Depends on the country also, the 2080ti / 9900K / 32GB RAM, 960GB ultra fast NVME and a 2TB SSD version costs £3,400 in the UK the BOM for those parts is at best equal and depending on the availability actually cheaper than buying them separately.

The Corsair One is the first pre-built I was actually considering buying because of its form factor, use of more or less standard PC parts and the warranty and serviceability of it.

It's only a $400 premium because of the discontinuation of the 2080 Ti. At historical prices, it would be an $800-900 premium.

Are we looking at the same Corsair One that runs $2,200 in its cheapest variant? Because I built a SFF form factor PC with equivalent specs and zero exotic parts that fits in a case the size of a console (Dr Zaber case), all for under $1500. It's a bit trickier if you want to water cool it, but I'm not sure why you need to if you use an AMD CPU (much better performance/watt) and don't overclock your GPU.

Put in a 2080ti or a 1080ti for the previous gen One an a 9900K in a Dr Zaber case and water cool them I would really like to see that.

You’ll need a DC-DC set up and a custom one to boot, and an external water loop.

Not to mention that even building an air cooled SFF build is hard, SFF components are rare in many countries and often require you to import it yourself which adds a big premium in the form of import fees, you also need an SFX PSU for that case and one of the smaller ones to boot as well as likely do your own custom sized cables to actually fit things in.

Once again, why do you need water cooling?

Wow, the One looks really slick. I've been wanting to do mITX for the next build but I think I may just buy it.