Looks like manufacturers feel they crossed a line allowing these giant-capacity machines and their huge drums spin at 1400 rpm. I loved spinning huge loads of bath linens at 1400 in the Maytag 8100, but often wondered if the stress of spinning a BobLoad at that speed was putting an undue amount of stress on the suspension, etc.
My top-loading Speed Queen spins at a leisurely 720 rpm, but since the dryer reaches temperatures rivaling the surface of the sun, loads of towels dry surprisingly quickly, LOL.