According to Anandtech in depth review, iPad air 2's NAND are quite fast.
http://www.anandtech.com/show/8666/the-apple-ipad-air-2-review/4
Actually I don't know which model they used.
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Shorter lifespan? Are you serious ? If MLC lifespan is 8/9 years, TLC will be 6/7 years. Still much more than you are going to keep your iPad.
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This thread is misleading.
TLC NAND doesn't automatically mean something bad.
Samsung's 840 ssd series use TLC NAND, are very popular, fast and reliable.
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So basically you are assuming that TLC means defective NAND?
Dude is this thread for real?
The most popular ssd sold in the world uses TLC NAND.....
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TLC aren't always slower than MLC. that's just not true.