Base Apple iPhone 7 is slowest
With iPhone 7, Apple gives you three choices for the main storage; 32, 128 and 256 GB. But it looks like the amount of storage is not the only difference. First reported by GSMArena and then tested again by Unbox Therapy, the 32GB iPhone 7 is 8 times slower than the 128 and 256 GB models in terms of the memory speed.
In UnboxTherapy’s test, a free app, PerformanceTest Mobile, is used to determine if there is a performance gap between a 32GB iPhone 7 and a 128GB iPhone 7. In the test, both of the models managed to get a similar read speeds ( 656MB compared to 128 GB’s model’s 856MB score ). However, the situation is different in the writing speeds. While the base model only managed to get 42MB per second in the writing test, 128GB model wrote at 341MB. This means the base model is nearly 8 times slower in the writing performance.
You can say those results have nothing to do in the real life, but it makes a different in the real different as well. When connected to a MacBook, the 32GB model wrote a test file in 3 minutes and 40 seconds whereas the more expensive model wrote the exact same file in 2 minutes 34 seconds.
The explanation, on the other hand, lies on the structure of the SSDs. Occasionally, SSDs with more capacities perform better in the memory tests as their controllers have more access to the NAND memory chips as described by How-To Geek.