The San Diego doesn't OC better than a standard Venice. If anything, you might get a worse OC with a San Diego, because of the increase of chance of failure rate with more transistors and an increased cache. I guess the San Diego core puts out slightly more heat/power... and this is like 1W more per 100W or something... very small. But I would go with the 3700+ over the 3800+ just due to the increased cache and probably equal OC ablity. But the cache increase is expensive to put on a chip and tougher to get perfect yeilds without some cache failure in manufacturing, so that would explain the cost.