TSGL: Hard Drive cache

[Don Penlington]

I'm looking to buy a 2nd hard drive about 250-320 Gb, probably Samsung, WD 
or Seagate.

I will probably use it as my primary drive, or may slave it for storage only.

I notice that some have 16Mb cache, others 32Mb. The difference in price is 
less than $10, other things being equal.

Is it worth paying an extra $6-10 for the larger cache?  Would I notice any 
real difference?

What does the HD cache actually do?

Don Penlington
 From the Beach at Surfers Paradise in sunny Queensland.
Computer tutorials, local scenery,  and other things at my website:
http://users.tpg.com.au/deepend/index1.html