« Last post by JeGX on June 18, 2015, 01:19:08 PM »
The Cache is always trying to guess what memory you’ll need to have before you request it, this prediction is called Cache Prefetching. This is why when working on an array it’s best to go through in sequential order instead of randomly jumping through, as the Cache Prefetcher will be able to guess what you’re using and have it ready before you need it. Cache loads things in groups of 64 bytes. The size is CPU-dependant and can be checked under your CPU’s specification under Cache Line size, although it’s typically 64 bytes. This means that if you have an array of integers and you grab 1 of those integers, the cache has also grabbed the Cache Line that it sits on. Grabbing the next integer stored next to it will be a Cache Hit and subsequently extremely fast. The alignment of the Cache Line will always be a multiple of the Cache Line's size, meaning that if you fetch memory at 0x00 (0) then what will be cached is everything between 0x00 (0) and 0x40 (64) and if you fetch something at 0x4F (79) then you’ll get everything between 0x40 (64) and 0x80 (128).
Full article: http://www.gamedev.net/page/resources/_/technical/general-programming/cache-and-how-to-work-for-it-r4020