Why partition it at all? Any decent imaging software will only image what's there, not the entire disc. Only time I would split an OS disc is if I planned to dual-boot with something else - and even then only if I didn't have a spare HDD knocking about.
Max score of a mechanical HDD is 5.9. SCSI/SAS/RAID may get more points but dunno. In any "normal" desktop you would need an SSD to get more than 5.9.
Exactly.
Sometimes it just isn't worth the bother installing software all over the place. I used to make that mistake years ago - small OS partition then struggle down the line when it fills up.
If you are worried about data [putting aside it should be backed up anyway] get a second HDD dedicated to storage.
I'll never fill up my Windows partition, all my applications and games go on my other partition, and I have a partition for storage too, I usually give Windows around 40-50gb, that's probs more than it needs.
It all goes back to when I had XP and kept on re installing it cause it was slowing down after 2 months, I nuked the local drive and thought to hell with re installing games and some applications, I'll put it on a desperate partition.
Just seems a mess really wacking all applications and games in the program files folder and storing all files on it too, seems abit crappy.