I'm asking if TRIM is enabled on iOS because, ever since I ran out of memory on my iPhone (have since cleared a few GB back), it seems to be slower than it was before. My suspicion being that, with most flash memory "sectors" now partially used, every write operation now takes longer…
Relying heavily on flash memory, I wonder if the iPhone implements TRIM (or any "trim-like" feature) to maximize flash memory performance and specifically if that will let me troubleshoot a slow phone and/or know if I would want to jailbreak the device to enable TRIM or otherwise control storage more tightly than iOS is delivered.
Best Answer
Since I'm just a generic curious who can do some research on the web, I'll make here some assumptions so we can be on the same grounds:
If you follow every link above deep enough, you may realize it's just not that simple. Even Android's TRIM support probably isn't the same TRIM as a notebook uses on its SSD.
So, it doesn't matter if it supports TRIM or not. The whole point of going with an iPhone is trusting Apple and letting them do the hardcore tech work. And the whole point of jailbreaking is being able to do things Apple can't allow for any reason, such as unblocking carriers. Anything else on JB is doing it wrong (specially now we have android, even for iPhone) - and I'm saying that from my heavy experience using jailbreak from iPhone 3 to 4.
Now, to address your main and unannounced question, best thing you can do to test if your hardware is malfunctioning is to backup your iPhone and reset to factory. Then fill it up with music or pictures, since you suspect a full disk is causing the malfunctioning, and avoid installing applications at all. You probably won't see any problem and, if you do, just send it to warranty. You can also send it to warranty directly, but you risk of it coming back and just losing few days there.