I went to the linked page and tried to make configuration changes - the same computer with and without Windows. I couldn't find that option.
On Dell's website, they let you do this to many of their workstation computers and it appears that the cost of Windows is around $200. What's interesting is that when they are clearing out stock and they offer some basic workstation configurations at $500 or so, you can still delete Windows and get that $200 off the price.
I messed with the low-end config a a bit, and it looked like the "Windows 10 Pro 64bit English,Spanish,French" license is more like around $100. Still a nice drop though. Too bad there's no way to choose "No OS installed", but maybe Canonical kicks them a little bit of money to offer Ubuntu.
It seems that in 2016 there was a ruling[1] that said it's not illegal to sell them _with_ an OS preinstalled (and included in the price).
> The CJEU ruled that it's legal to bundle PCs with software without indicating their prices separately, and that offering consumers no choice but to buy the PC with the software is also legal, "unless such a practice is contrary to the requirements of professional diligence and materially distorts or is likely to materially distort the economic behavior of the average consumer with regard to the product, a matter which is for the national court to determine by taking account of the specific circumstances of the case in the main proceedings."
I’m pretty sure it’s Microsoft that pressures manufacturers to not offer PCs without operating systems not “Europe”.
I don’t think they ever went as far as threatening companies for selling Linux systems but it’s well documented that they withdrew discounts from suppliers offering OS/2 with computers.
Microsoft did that after the US government made them stop charging for a Windows license after every computer a vendor shipped... regardless of the OS installed.
IBM just included a copy of FreeDOS for every PC before it sold it's business to Lenovo.
The product specifications reference or PSREF is the usual place to compare Lenovo stuff - Oddly enough, you can't filter the operating system section for the Ubuntu options (product codes 30BFS6EL00, 30BFS76F00, 30BDS4T000, and 30BDS4T100 for various combinations of an NVidia RTX 6000/8000 and dual/single socket processors):
Not sure if this covers your question, as the OP said "the same computer with Windows and Linux available" but at least you can probably find the equivalent Linux machines here and then compare to the previously found Windows systems.
Just do a websearch for "Dell Workstation". Look at the Precision 3630. Some say "Precision 3630 Tower Workstation" and some say "Precision 3630 Tower". Scroll down and you'll see that where it lists the operating system, the systems that say "Workstation" all have a "show all options" listing.
Customize the one that is currently listed at $579. It has an i3-9100 processor and switching from Windows 10 Pro to Ubuntu will subtract $109.27. But if you then switch the processor to the Xeon E-2246G, then changing from Windows 10 Pro for Workstations to Ubuntu is a price reduction of $264.36!
As an aside, I find it hilarious (and nice) that you can save a couple dollars by specifying no keyboard or mouse. Sometimes, you'll even see the option to have them skip shipping you a power cord for $2 off or something.
On Dell's website, they let you do this to many of their workstation computers and it appears that the cost of Windows is around $200. What's interesting is that when they are clearing out stock and they offer some basic workstation configurations at $500 or so, you can still delete Windows and get that $200 off the price.