San Diego core is better with a higher 1MB L2 Cache while Venice is only 512KB. Both use 90nm process. The older cores like the Newcastle, Winchester, Clawhammer, you don't want to touch. Too old for CPU. San Diego and Venice are two new CPU cores with San Diego being the best.
Dual cores, Toldeo is better than Manchester core because of the increased L2 cache. Anything with higher cache, I'll take.