vietanh.ngdinh :
Hi I was wondering if i'm thinking a 2048kb cluster size would help my hdd compared to 64kb cluster size. Is it true?
It depends on what type of files you are primarily working with -- 64KB is good for very large files (like multimedia or big databases) on a storage drive. If you mostly deal with text documents that are smaller you are better off with a smaller cluster size to avoid wasting a lot of space.
As for your OS drive 4KB or 8KB probably makes more sense since the files are smaller and will not result in as much wasted space. And if you want OS drive performance you should be looking at SSDs.
It is also important to consider the size of your total storage array -- probably something that will not be an issue for you, but large partitions require larger cluster size since the number of clusters is limited to 2^32 and a cluster size too small will limit the maximum partition size. 4KB can only give you a 16TB partition, while 64KB will allow partitions up to 256TB (not something that the average user has to worry about).