Before computers completely take over the hedge-fund industry, they need to overcome one tiny obstacle: investment returns.

In the first half of the year, computer-generated strategies, or what they call in the business, systematic strategies, returned 3.17 percent, according to data by Preqin. That compares with the more-traditional discretionary strategy, which returned almost double that, with gains of 5.99 percent. Those results are net of fees.

Discretionary strategies depend on the skill of the humans making the investment decisions. And it was the human side of the hedge-fund world that helped drive total industry returns in the first half of the year, to 4.87 percent. That's the industry's best six-month performance since the beginning of 2009, according to Preqin. At that time, though, hedge funds generated returns of 16.9 percent.

Hedge funds still trail the broader equity gauges. The was up 8 percent over the same six-month period. So it makes sense that the long/short equity and activist strategies were the best performers, returning 6.5 percent and 6.2 percent, respectively, according to Preqin. Macro and relative-value strategies were positive for the year but each returned less than 2 percent.

Hedge funds tend to outperform during bear markets – and the U.S. has not experienced one of those in years. That helps explain why hedge funds have dealt with outflows in recent years.

In an attempt to keep investors and boost returns, hedge funds have been embracing technology, be it through strategies that use computers and mathematical models to pick stocks or that use big data or machine learning in selecting and maintaining portfolios.

A recent Credit Suisse report found that almost 60 percent of investors surveyed planned to increase their exposure to quantitative strategies over the next three to five years. Only 4 percent said they would decrease exposure, with the remainder choosing to maintain the same.

Like all things, performance go in waves, but the computers will need to do a bit better to justify all this interest.