Computer system

Can't say.  You forgot to post what model you are referring to. There are hundreds of different OptiPlex models.

Systems that will run 8.1 will run 10

There is no such thing as 10.1

8.0 is end of life.

NO PC stated. at all.? sure./...

consider this wiki page, first. look see and tell. (wiki is the best no?, if not fix it !)

and I can tell you CPU very old that runs 64bit.  ive tested them my self, amd and intel.

I have dell 380 running w10-64bit with SSD boot, and all chips on the mobo work perfectly.

the worst are OLD AMD with or any chipsets that are marked NFORCE, AMD ended support long ago there.

and Dell did sell both kinds. a fact. optiplex 580? id avoid. avoid all Nforced series up to #7 , (legacy)

one thing to consider is as MS advances, new version of w10 (v1909 ) now,  the newer verison can fail for older chips the makers do not update (ADM tops my list for Chipsets here)

Best is to invest in gen4 or newer I3,i5,i7 and up CORE CPU based PC< so there is a W10 futures. see?

Intel too is dropping support, as each newer OS updates to a newer major build.(for their older chips)

there web site clearly states GEN 4 up CORE. (for a future) consider that, if buying, used PC's

DOES YOURs? or CAN it run,  W10,  ? (the 2nd question ANWSERed;   most can if you know how)

FOR SURE  2005 AND UP CAN (most) with matching and correct CPU. Penium D up.(ask)

w10 32 bit or 64,  IT MATTERS and 64bit is far far the best,  (a goal needs to be here  64bit)

no PC stated optiplex is not a PC it's  category, class.  (post a photo first?)

first off  w8 is not sold now, its GONE now. (ebay, oddities excepted)

second off , no CPU stated buy you at all.  and that matters first then chipset and BIOS last.(BIOS upgraded sure)

w10 64bit runs even on

P4  (Pentium D ,D940)

and AMD,

I have w10-64 bit running on all PCs here, even old 380 Core 2 DUO and Quad.

and chipsets back to G31.  even 945G

and super old Athlon, 64x2 (stepping F2)

even 32bit w10 on relic laptop Dell D520 laptops (attic stored) (used for very custom software )

ive tested w10 on many mOBO and CPU back to 2005

but no PC told at all,  the PCs has service tag to see true name and model.

you can post a photo off it, and BINGO.