HDD space and cache

[sheky]

Besides space allotted on a HDD i've always thought that RPMs (the speed the HDD reads/writes to itself) was the only other main significant part. Although after doing some more research I've realized that companies have been stressing a rise in cache, what does this do? And btw, does ram take info from the HDD as fast as the RPMs writes to it (in other words does RPMs matter as long as you have enough ram (in writing case)). Thank you!

 

[foxhound]

The RPM = the speed the hard drive spins at, thus allowing faster writing/reading. with faster hd's you get more cache, this allows the pc to read stuff (like parts of a movie) in advance and cache it in the cache memory making it read faster (wont notice difference in a movie though. but might notice it when copying large files). The amount of ram doesnt matter since your connection from your hd to motherboard is probably a lot slower than the ram writes at. Cache is worth it though on a hd, specially if you work with large files.