As covered, the minimum price for a drive is not dictated by the capacity, but the hardware to make it. - the case, the motor etc. That's largely the same for a 1TB drive as a 4TB drive as a 14TB drive. A 1TB drive vs a 4TB drive may have less platters in it, but they're not the expensive parts. 'much' is debatable, but faster yes. modern drives often have more cache on them, and the aerial density is greater so data from the platters through the heads will be faster and better voice coil motors mean head movement is faster. it'll never be fast like SSDs are, but they have improved, and they're still much cheaper than SSDs (in GB/$ - price up a 4TB SSD).