X86-Secret : ES Zone
PIII Xeon 550 1M ES  (Week 19, Year 1999)   
Intel Confidential QB75ES / Y9199008-0111 IRELAND / i'98 80525KY5501M

An early sample of the Pentium III Xeon clocked at 550 MHz and featuring 1 MB of L2 cache. This Enginnering sample was built on an unmarked cartridge in March 1999, some weeks after the 2M version.