It’s correct, and higher is better, 7K2 is faster and often longer lasting somehow. Generally better built. Downsides are noise, power draw and thermal.
They sourced drives from former HGST under WD but 5K4 we’re not available so marketing rebadged 7K2 as “5400rpm-class” and lucky buyers were hit with better performances.
Sort of. The WD Red drives outperformed actual 5400 drives but underperformed other 7200 drives by a large margin (180MB/s vs. 230MB/s), while not necessarily offering heat or noise benefits that matched. My current 8x8TB WD Red Unraid build will likely be the last WD drives I buy for a long time.
They sourced drives from former HGST under WD but 5K4 we’re not available so marketing rebadged 7K2 as “5400rpm-class” and lucky buyers were hit with better performances.