Trader A, IMO. As mentioned, if ROI and Drawdown and all stats are the same so inherently portfolio volitility will be the same also. I chose Trader A, because they are specialized in those few pairs along with a strategies for different market conditions of those pairs. This type of trader is better because trades will come to them versus Trader B where they are constantly looking for traders. Therefore, Trader A would have a less stressful lifestyle and more time to enjoy the trader lifestyle.