X86-Secret : ES Zone
Pentium II 400 MHz ES  (Week 04, Year 1998)   
INTEL CONFIDENTIAL / 80523PY400512 Q434 ES / O80401CRA0-432 A4
INTEL CONFIDENTIAL / 80523PY450512PE Q561 ES / 98280434-0976 MALAY

Here are two engineering sample of the Pentium II 400 MHz, clocked at 4*100 MHz. The first one (Q434) is an early ES based on the Deschutes (0.25 ┬Ám) core. It was built in January, 1998, 4 month before the official Pentium II 400 launch. The second one (Q561) is based on a later revision that include 512 KB L2 cache with ECC ("PE" marking). It was built in July, 1998.