Hard drive cache size question?

[ingeborgdot]

Seagate came out with a 500gb hdd that has a 32mb cache. How important is cache size? Will it make much of a difference in speed? Would it be more important to have the 32mb cache size on my os hdd or as my video, pics etc. hard drives? Please let me know what you understand about cache size on hdd because I don't for sure.

 

[bushwhacker]

Generally, the more cache, the faster your programs loads.

The more cache, the more expensive it gets.

 

[Nodsu]

The on-disk cache size is rather irrelevant. You can expect some 1-2 percent improvement between 8 and 16 or 16 and 32 MB of cache.

As I have explained many times before, the caching that your OS does is much, much more intelligent and the amount of memory involved is at least 10 times as big as the hard drive cache. A modern OS completely overshadows the on-disk buffer and you can see the difference in (useless) benchmarks that disable OS caching.

If we actually got some decent 256 or 512 megs of cache on disks like we have on proper RAID controllers, then it would make a difference.

 

[technicalfury42]

RAID controller cache helps to promote I/O throughput over a static number of I/Os the hard drive(s) can provide. They often have backup power.

One of the (many) problems with a hard drive cache so large is that you can corrupt / lose data easier in the event of a power outage.

Hybrid drives are going to address that completely, eventually, through the use of nonvolatile memory:

http://en.wikipedia.org/wiki/Hybrid_drive