Answered Hard disk differences!

[beecee]

I am in the process of setting up a nas, and looking at different hard drives, wd seem to be the best, but them they come in red, green and black. Which ones would be best, looking at 4tb drives,

 

[andy1249]

Red are the ones they push saying they are specifically designed for nas units.
Supposed to be balanced better for 24/7 always on usage.

However, really, any of them would be fine.

 

[EndlessWaves]

It'll be the workload rather than the device they're optimised for, so ideally you'd avoid a green drive with it's aggressive power saving in a use with a lot of sporadic disk activity so it didn't keep spinning up and down.

Red drives are designed for exactly that situation, blue drives are somewhere in the middle, black drives are performance-focused and purple drives are designed for constant writing.

It depends on the pricing really, I wouldn't pay 20%+ extra unless you're absolutely sure it's the best suited to your use. Otherwise, pick between whatever's on offer at the moment.