More than 500k IOPS was downright common for PCIe gen3 SSDs. 1M IOPS is totally achievable with one high-end gen4 SSD. If you meant IOPS with a queue depth of

More than 500k IOPS was downright common for PCIe gen3 SSDs. 1M IOPS is totally achievable with one high-end gen4 SSD. If you meant IOPS with a queue depth of one, or sustained write IOPS, then you need to specify those extra conditions before calling vendors liars. No high-end drives implement the NVMe Host Memory Buffer feature, let alone rely on it for maximum performance. You can buy an Enterprise QLC drive that is fully capable of 800k IOPS for reads. TLC drives that can do twice that are available. Those drives don't have SLC caching.