I was looking at model numbers supported by Coreboot and the associated sockets. According to the table I was reading, socket_6xx means P4 so it has SSE and SSE2.
It is a little grey.... model_6xx is a big clump of PII, Celeron, and PIII's. According to Intel docs the P6 family includes Pentium Pro, PentiumII, Celeron, and PIII processors. P4 and XEON are the first of the IA-32 family.
I still think we should source all of the models for the intel CPUs.
Yes I never liked how the model_6xx is all clumped togethor. I think they should be seperated by family/model. But that may be for another day...