There is definitely a noticeable difference in speed between the iPhone SE and the iPhone 6s, and it is important that you know all about it, especially if you are trying to choose which of these phones you want.
Although both of these phones have the same A9 processor in them, some Apple iPhones with the same processors have had different speeds in the past.
While the iPhone SE and iPhone 6s are identical when it comes to speed, tests with both of these devices revealed that they are off by a few points on the single-core and multi-core tests.
Those who use both of these devices will find that they offer the same speed more or less, whether it is scrolling, loading applications, swiping, or doing just about anything else.
The few points that separate these phones on the speed test are fairly insignificant, meaning there is no real noticeable difference when using each of them side by side.You can see two benchmarks (Geekbench score) of iPhone SE and iPhone 6S.
For Geekbench score Single-Core score you can expect an higher value for iPhone SE (2538 points vs 2292). The same happens for Multi-Core score. iPhone SE has an higher score (4421 vs 4293) in these benchmark test results.
Although in the past Apple hasn’t been great with making different phones with the same processor the same speed, these phones are identical when it comes to this particular component in every way.
Conclusion: you can expect similar performance of iPhone SE comparing with iPhone 6S despite of a lot of speculation regarding to iPhone 6S to be faster than iPhone SE because of the higher price. For $399 you get an iPhone that in terms of performance is similar to iPhone 6S.