One machine or two?

[MAXBattle]

I have a couple of older boxes that I want to put to use (and save money).  One would be an "ingest station" for assorted audio and video (copying from old tape media to digital, etc.) and one would be for backup of my main machine.  The media box has a 990FX mobo, FX-8350, and the appropriate media cards.  It'll run Win7 for conversion card compatibility.  The planned backup box is older and has an Athlon 64 X2 CPU.  I have an assortment of new (or light used) SATA SSD's (250GB & 500GB), a few good 2TB HDD's and a brand new 8TB Iron Wolf drive for the backup.  My main PC runs Iron Wolf pros in RAID for data drives, so the separate backup is truly Plan B (or even Plan C).

I'm wondering if I should make one machine or two.  The advantage would be that the backup machine could run non-Windows, but then I'd have one more machine taking up space.  I only want to repurpose old parts.  If I didn't, I'd just buy a Synology NAS for the backup and call it good.  I'd likely run the ingest/conversion during the day and backup at night, so there wouldn't be a usage conflict if it was one machine.