Huh weird I do have experience of this happening especially on used drives that are technically beyond their lives, +7 years etc, guess it depends on manufacturer and classification since you haven’t personally experienced it. When I say slow down I’m referring to the read and write speed not the platter rpm even though that could happen such as with motor bearing wear. There’s really multiple potential hard wear issue that could cause read and write speeds to slow down: head wear, platter degradation, etc. Although i do want to clarify that I’m not necessarily saying its dying or even if its 100% a hardware issue since fragmentation could be the cause. Not even sure if it’ll be throwing out errors yet so I can’t wait to see what OP updates us with.