[3] PSE-36 was introduced into the x86 architecture with the Pentium II Xeon and was initially advertised as part of the "Intel Extended Server Memory Architecture"[2][4] (sometimes abbreviated ESMA[5]), a branding which also included the slightly older PAE (and thus the Pentium Pro, which only supported PAE, was advertised as having only "subset support" for ESMA).
PSE-36's main advantage was that, unlike PAE, it required little rework of the operating system's internals, and thus PSE-36 proved a suitable stopgap measure[6] around the Windows NT 4.0 Enterprise Edition timeframe.
[8] Despite this, AMD and later Intel chose to provide up to 40 bits PSE support in their 64-bit processors, when operated in legacy mode.
[10] As long the processor (as indicated by cpuid) and chipset support PSE-36, enabling PSE alone (by setting bit 4, PSE, of the system register CR4) allows the use of large 4 MB pages (in the 64 GB range) along with normal 4 KB pages (which are however restricted to the 4 GB range).
[11] The total amount of physical memory addressable in AMD64 legacy mode using PSE 4-MB pages is, thus, 1024 GB.
[16] The tuning documentation for the latter noted however that "Unfortunately in most cases performance gains obtained using the PSE-36 driver are not spectacular.
[...] After more than a year of experimentation and tuning, Microsoft and IBM dropped support for PSE-36 due to insufficient performance gains.
[3] The Intel Extended Server Memory Architecture is defined to include two 36-bit addressing modes in the core processor: PAE-36 and PSE-36.