trstew said:
I was down to 17% and starting to notice the drive bogging down some...
It sounds like you are either recording a lot of content, are using small HDDs, or maybe a little of both.
Unlike PC HDDs, the storage protocol for DVRs is different and the HDD will not slow down simply because it is getting fuller. That is typically a function of fragmentation, and in the DVR storage protocol there is no file fragmentation (although there is free space fragmentation, which is harmless). I have run HR2x HDDs full many times without any slowdowns or adverse reactions. If your DVR is slowing down, that is for another reason (and there are plenty of other reasons out there, sadly).
If you think about it, this makes a lot of sense. The HDD is instructed to write to free space or read from written files. Both exist on the HDD in the same state regardless of what has been written to other places on the HDD, so previously-written files are completely out of the equation when the HDD attempts to read or write a file. The HDD neither knows nor cares what might or might not be written elsewhere on the drive; it is only interested in a particular file or a particular free space location, so there is no way that pre-written files can interfere with that process.
Folks find new DVRs faster, but not because the HDD is empty; its typically because there are not any SLs set, and when you set a new one it has to rectify all possible conflicts in serial order then and there with each of the previous ones, which grows exponentially with the number of SLs.
There is one exception to KUID that those not intimately familiar with HDDs should take into account, which is that if you set for KUID older programs will not be deleted to make space for new recordings except under one particular circumstance, which is if you set the DVR to record a finite number of episodes of a particular program. If you set the DVR to record 10 eps of
The Finder (well, there are only about 8 left so bad example) or
The Mentalist (lots more of those to come), when it goes to record ep #11, ep #1 will be deleted, even if KUID is set in preferences.