Does iphone memory determine speed like what can be compared to a pc ram?

Me and my younger brother both owns an iphone 6 but his' got more memory of 64 gb while mine is only 16 gb, i tried to compare their performance by simple swiping the screen and it is quite noticeable that my brother's phone moves smoother and crispier, while mine is experiencing a slight matrix or a slightly lower frame rate, does iphone memory determines speed and performance or does it only refer to storage space?

No CPU & ram determines that not your usually memory…

It refers to storage, but storage also has an impact on performance, especially when you have lots of apps, emails, photos, videos, etc. Using up that storage. 16GB is almost useless these days on newer iPhones unless you have almost nothing on it and simply use it as a phone.

That is not memory, that is storage space. Memory is RAM, and usually smartphones have 1 or 2GB RAM. RAM determines speed more than storage space does. However, having less than 1GB of storage space free CAN impact performance.
what affects speed MORE (on both a smartphone AND a PC) is the CPU speed.