The HMB size is 200 MB, which is more than the 64 MB that we're typically seeing on DRAM-less SSDs.
At small work area sizes, the SN580 is more than twice as fast, with work areas of around 40 GB, that gap even increases to 400%! This is where the magic is—algorithms.
Our testing reveals that the SLC cache is sized at 341 GB, which means the drive will fill all of its capacity in SLC mode first. This is a huge improvement over the SN570, which came with a tiny 12 GB cache only that got filled up in the blink of an eye.
WD was smart to set the thermal throttle point very high, at 105°C, which provides enough headroom for workloads to finish, so the drive can cool down again. I'm surprised though that the thermal sensors are so inaccurate, they claim 88°C, while we've measured 106°C surface temperature. No big deal, still worth knowing if you plan on trusting software temperature readings. What helps to make the difference is WD's energy-efficient controller design, which means reads and writes result in lower heat output—good job WD.