Pentium 1-4 - older single core chips
Pentium M - older single core notebook chip (Core2 and I series based partially on this design)
Pentium D - early dual core chip (two pentium 4s stuck together)
Pentium Dual Core - based on Core2 chips-usually has less L2 memory on chip
Pentium G series - based on I-series-again the economy version of I series
Intel is confusing with naming
and I never have been too sure what Nehalem exactly is.....