If you look at the currencies for the US Dollar (USD) to Japanese Yen (JPY), as of 9/21/14, 1 Dollar (USD) = 109.02 (JPY). Again, as of 9/21/14, the conversion for 1 USD for Chinese Yuan = 6.14 (CNY). However, as of 9/21/14 the currencies for 1 Japanese Yen to Chinese Yuan = 0.056 (CNY). As you can see the US Dollar is worth a lot more for the Chinese than the Japanese Yen is, in fact it's worth about 6 times more. So if you were to spend your days farming gold for real money which type of server would you choose? Of course, a North American or European server, because as of 9/21/14 their currencies are worth approximately 6-8 times more than the Japanese Yen.
So if you want to play on a server where gold farmers are non-existent, play on a Japanese or Asian server, because I can assure you no gold farmer would have the right mind to try and sell their in-game gold in a currency that's worth-less than those in the western servers.