It gets better. Portfolio 2 is the Bogleheads four-fund with 10% borrowed from the standard investments and allocated to gold. Portfolio 1 is standard four-fund (50% US stocks, 30% foreign stocks, 10% aggregate bonds, 10% TIPS bonds. The return is better, the drawdown is better, standard deviation, Sharpe and Sortino ratios (measures of risk-adjusted return). What’s not to like? 10% is what Clark thinks is acceptable to allocate to gold. Personally, I prefer more, 15%. TIPS data limited to 2001 onward.
