2500 vs 4000 memory understanding...

If my 2500 comes with 16mb of onboard memory expandable to 128mb, and a 4000 comes with 272mb of onboard exp. to 512mb...then what is the 80gb hard drive on the 4000 for? I mean i thought the hard drive was used for memory. Pleez help me comprehend this and I hope I haven't confused any1.

Did you ever use a usual PC?

Content of RAM memory (that's the 16/128/512 MB) is lost when you turn the machine off. But it's much faster to access than a mechanical drive.

Hard disks are used for long term storage, but they are slower to access, thus not really suitable for real time sample playback and editing.

That's why you load samples into RAM memory from your hard disk memory, and why you need both in a machine to work properly.

the onboard expandable memory you're talking about is ram which is used when you load sounds into the mpc to play from the pads.

The hard drive you're asking about is for storage of samples, not for playing sounds.

Example, you store sounds on the hard drive and load them into tha ram when you want to use them. The ram and hard drive are used for completely different things. The hard drive related more to the CF cards you use with the mpcs. for storage not playing.

Thanks Stilo and Cybananna that was killing me.