Pentium E6200 is good or pentium D925 ? Just for gaming

Not what you wanted to hear (you undoubtedly wanted just a simple answer), but we really need the brand and model of your motherboard. Not all LGA775 motherboards are compatible with all LGA775 CPU's.

The E6200 was never officially released. It was an engineering sample (ES).

All Core2 Duo CPU's are superior to any LGA775 Pentium 4 CPU.