Even on a freshly formatted drive, you'd want your write rate to stay below what the SMR rewrite process can handle. If the drive fills up and it needs to delet

Even on a freshly formatted drive, you'd want your write rate to stay below what the SMR rewrite process can handle. If the drive fills up and it needs to delete something to make room before writing new video, its ability to keep up with the incoming video data is going to be reduced. Lots of recording systems won't record unless the camera sees motion. Or they record at a much lower frame rate until motion is detected & then go into high speed mode to capture fine details. So that helps, and the CMR buffer also helps. But if the recording fills up the CMR buffer, you're back to incoming data potentially arriving faster than SMR can rewrite. Time to drop back to 1080 HD cameras from 4k cameras maybe. Or reduce the number of cameras. edit This is comparing a SMR to a similar CMR drive. Obviously, any drive can run into trouble if you exceed its write capabilities. But a SMR drive's write rate is going to be lower than a CMR drive, once it's buffer area is full. And especially if you're doing random writes.