UPDATE: CyanogenMod 10.2.1 has trim enabled. Don't follow these directions. Just install 10.2.1.
I have a Nook HD+, and the only way to love this tablet is to put CyanogenMod on it, because that turns it into a very-near stock android tablet - no special Barnes & Noble stuff, and it gets really really fast.
This tablet has one huge flaw. The memory controller has a tendency to fail when the system runs a trim operation, something that all modern Android devices have that helps keep them from slowly starting to lag more and more over time. Here is a decent description of what trim is and why you want to have it on this device. The solution until now, even on the stock HD+ from what I can tell, is to just disable trim completely. So, what happens is that, regardless of if you are running the stock firmware from Barnes & Noble, or if you have upgraded this tablet to CyanogenMod 10.2, this tablet will progressively get slower and slower until it is nearly unusable.
But, there is a solution, if you are willing to to take a risk. Apparently, the Nexus 7 has the same memory controller as the Nook HD+, and Google has patched Android to fix the bug. There hasn't yet been enough confirmation that this is fixed, so it isn't in any mainstream kernels that I can find. But, if you are running CyanogenMod 10.2, you can flash this kernel right over your CyanogenMod 10.2 nightly and trim will be enabled. Once it's enabled, you can run this app to fix the lag. After running the app once, it'll probably be a while before it needs to be run again, so in case there IS a bug, just re-flash CyanogenMod Nightly to put the original kernel back.
So, to recap the steps to make the Nook HD+ not lag when running CyanogenMod 10.2:
- Download the patched kernel zip.
- Install the lagfix app.
- Use CyanogenMod updater to get the latest nightly ready to go.
- Reboot into ClockworkMod.
- Flash the new kernel and reboot.
- Run the lagfix app for all partitions.
- Reboot into ClockworkMod again.
- Flash the latest nightly zip (which will swap in a kernel without the fix for protection).
- Enjoy Fast Tablet.