Small correction, a significant amount of Chinese migrants are from Fujian, which borders Guangdong. You can usually tell from the language spoken—Fujian descendants speak Hokkien while Guangdong descendants speak Cantonese, though it's not a hard rule with the regions being adjacent, of course.
In countries like Malaysia, it seems to be an even mix of both but in others like Philippines 90% are actually from Fujian.
Read up on Chinese migration from Guangdong during the US gold rush and railways and why they left.
Eventually, Chinese people in nearly all countries rise to the top of the income/wealth chart. For example, the richest group of people in Vietnam, Philippines, Malaysia, Indonesia are all descendants of Guangdong people who migrated. In Indonesia for example, Chinese are 1-2% of the population but owns 70% of private wealth.
Fun fact, most Chinese people in China do not eat dim sum. Dim sum is a cuisine popularized by Guangdong (Guangzhou/Hong Kong area). There are also many regions in China that don't even eat rice. They eat bread or noodles mostly. Chinese image outside of China are heavily influenced by a small area in Guangdong due to immigration.