Read/writes slow over time badblocks burn in

[warriorcookie]

I've got a couple 4TB Ironwolf drives I'm burning in with badblocks.

I've noticed at the start of the pattern the drives start off at 185MB/s and then starts slowing down slowly until it finishes the pattern at roughly 90MB/s.
It's consistent behaviour for both read and write for 3 patterns so far. It hasn't started 0x00 yet. Is this the normal speed difference from outside track to inside or is there something else going on?

These 2 drives are connected to a H200 flashed in IT mode. Nothing else is connected to it. The other drives in my system are connected to a different HBA.

 

[Redcoat]

A couple of 4TB CMR WD Reds that i just finished qualifying yesterday showed the same characteristic at almost the same values.

 

[warriorcookie]

Can anyone explain to me why this is happening? I'm curious and would like to understand what's going on under the hood here.

 

[danb35]

Is this the normal speed difference from outside track to inside

Pretty much.