Then they are not fit for purpose, which is a completely different ball-game
Not technically true … maybe I didn’t explain this well enough.
Historically any burn to a writeable CD/DVD was an uninteruptable process … once the burn had started it had to complete with no interruption to the flow of data to the drive, otherwise you would get a buffer underrun error.
Think of it like this … once the disk is spun up to speed, the burn laser turns on and starts to move, creating a spiral that starts at the middle of the disk … the movement of the laser is a uniform process, so if data stopped flowing to the drive there would be a gap in the data spiral written to the disk.
The standards for data CD/DVD’s for PC’s doesn’t allow for gaps, so the disk would be scrap … not to mention the disk would not be “closed” properly.
Later on, the drive manufacturers (Sanyo, IIRC) came up with technology (BURN-Proof) that would (under ideal circumstances) allow the drive to seek the last place the disk was burned to, and pick up the burn from there … but the important clue is “under ideal circumstances” … te technology used in optical drives was never meant to be that accurate, so it was always going to be an "it might save your disk if you’re lucky kind of affair … it was never guarantted to save every burn, and it always worked best (but still only occasionally) at low burn speeds.
It’s reliability is also affected by optical disk quality, ink quality, and obviously wear of the moving drive components.
CD/DVD’s have always been, and will always be more likely to succeed if the data is comming from a hard drive rather than a MUCH slower optical drive … there is no arguing this point.
If and when I do any burning, I would not be doing anything else to occupy the CPU/RAM
YOU don’t have to … the OS itself may do something such as reorganising it’s HDD data, clearing of disk caches or any other general I/O operation … this is also MUCH more liable to occur in a system with multiple drives.
It’s HIGHLY unlikely to be the CPU that’s the bottleneck here … it will be input/output operations (read/writes to disk).
I’m not making this up ??? … disk to disk burning simply isn’t worth the risk (or the slowing of the burn speed to mitigate the risk), a modern drive will read a disk and write it to the HDD in a couple of minutes, the only time it may take longer is if it has trouble reading parts of the disk and has to make multiple attempts at re-reading … but that is PRECISELY one of the situations that could cause a buffer underrun in a disk to disk burn … IMHO, it just aint worth it.
Lecture over … if you decide not to listen, that’s up to you … as I said, the setting to enable the other SATA ports will be in the BIOS somewhere, but without sitting in front of your PC, I can’t say exactly where.