The “Allocation Size” used by Windows when it formats has nothing to do with how the data is stored on the physical disc, per se. Unless you’re using an “Advanced Format” disc, or something like that, basically all hard drives store the data in the same 512-byte sectors on the disc.
What the “Allocation Size” is is the smallest amount of space on the disc that Windows will use for each file. If you have a one-byte file, it will still “use up” 4096 bytes of disc space if the disc is formatted with 4k allocation units (i.e. it will use 8 of the 512-byte disc sectors to store that one byte).
Since your files will never be a number of bytes equal to an even number of allocation units, on average you “waste” half of an allocation unit per file stored – some will spill over a few bytes into the next allocation unit, and some will be a few bytes short of full.
If you have nothing but small files, then yes, larger allocation units are a problem, because you are using 4k (or 8k, or 16k or 32k) worth of disk space to store each 30-byte file, and most of your HD space will end up being “unusable”.
But using the small allocation units doesn’t necessarily hinder large files to the same extent as large units does with small files. You still end up “wasting” less disc space with small units… but you do end up with larger File Allocation Tables for the OS to sort through.
So you won’t be “hurting” your drive to use 512-byte allocation units and large media files. (But you _ would _ be wasting a whole bunch of space to use large allocation units with small files.)
Lol - the Seagate drive can’t be formatted with 512 byte sectors! A long, harsh and painful lesson has been learned here - this HDD is not a good bit of kit to get if you want to use it with the WD TV player! Another poster on a different thread has mentioned partitioning the drive works. I’ll give that a go and see if it works…