Intel Celeron Willamette processors were the first Celerons based on NetBurst micro-architecture. Willamette Celeron CPUs featured 400 MHz Front-Side Bus, long 20-stage pipeline, SSE2 instructions and enhanced branch prediction. These Celeron processors were produced using 0.18 micron technology and had the same voltage as Pentium 4 Willamette processors. Level 2 cache size on the Celeron microprocessors was twice smaller than on Pentium 4, which resulted in about 10% lower performance of Celeron processors. Smaller L2 cache was the only difference of these CPUs from Pentium 4 processors with the same core.