USB certainly adds its own lag compared to drive in SATA cable, but that's not noticeable to human.
Though some external USB optical drives might be based on laptop drives, which might have some design points aimed at lowering power consumption.
Anyway internal optical drive behind door certainly won't break looks.
And unless giving current PC to someone optical drive of it might well be SATA model and reusable.
To the OP, I too had the need for a DVD writer but also needed the SATA port it was connected to.
Using a Lite On external drive with no issues whatsoever.
Guys, thank you. I wouldn't expect any issues with an external drive as such, and wouldn't have thought the speed of the interface itself would be a limiting factor in practical terms.
This hopefully illustrates what makes me question the performance of internal vs. external. As I said, it's quite possible I'm being a bit thick.
liteon external
DVD-ROM Read Speed 8X
DVD-R Write Speed 8X
DVD+R Write Speed 8X
DVD -R Dual Layer Write Speed 6X
DVD +R Dual Layer Write Speed 6X
CD-ROM Read Speed 24X
CD-R Write Speed 24X
CD-RW Write Speed 24X
Asus Internal
DVD-ROM Read Speed 16X
DVD-R Read Speed 16X
DVD+R Read Speed 16X
DVD-RW Read Speed 8X
DVD+RW Read Speed 13X
DVD-RAM Read Speed 5X
DVD-R Dual Layer Read Speed 12X
DVD+R Dual Layer Read Speed 12X
DVD-R Write Speed 24X
DVD+R Write Speed 24X
DVD-RW Write Speed 6X
DVD-RAM Write Speed 5X
DVD+RW Write Speed 8X
DVD -R Dual Layer Write Speed 8X
DVD +R Dual Layer Write Speed 8X
CD-ROM Read Speed 48X
CD-R Read Speed 48X
CD-RW Read Speed 40X
CD-R Write Speed 48X
CD-RW Write Speed 24X
I have Plextor and sony internal drives from old pc, one was made in 2004, the other 2005 (both IDE). Probably due for an upgrade
It's E-ATX full tower cases which make normal ATX motherboards and gaming graphics cards look small.
Like my current case during first built into it almost decade ago:

Of course those cases also take lots of space...
Antec P280 is one of those bigger cases with reasonable pricing.
https://www.overclockers.co.uk/antec-p280-super-midi-tower-case-gun-metal-black-ca-168-an.html
https://www.anandtech.com/show/5090/antec-p280-when-enthusiasts-are-engineers/3
https://www.techpowerup.com/reviews/Antec/P280/5.html
Yeah that's a big ass case, mate! To be honest although I like (and very much appreciate) the suggestions given, I'm thinking I might still go with the pure600 because it should do everything I want, and it has the drive bays where I'd like/expect them to be. If I find it gets a bit warm in there, I think I can raise the lid and/or add some cooling, or even buy a different case with better airflow if it's really that bad.
@orbitalwalsh did you get your 4000Mhz RAM working nicely on the Aorus Ultra?
Maybe somebody can put my mind at ease about the RAM problems (I've read on the Ryzen thread) that some folks have apparently been getting with these processors? Also slightly disconcerting to observe
@8 Pack 's lack of enthusiam for the new X470(?) boards
No I won't be reviewing them. For me so far the new platform is not that great.
and this insight on the processors
3200 on amd imc is not a given you know.... Intel sure but some amd imc are just junk.
I'm not encouraged by this and makes me wonder whether to reconsider my CPU choice. I want my new stuff to work, not pay a huge amount of money for a lottery ticket/box of headaches.