If attention was awarded based on performance, silver miner ETFs would be getting a lot of airtime. Silver has put up a strong performance over the last two months, entering the the third quarter (Q3) at a loss and exiting with a gain of 25 percent. Even more impressive, however, is the performance of the funds that track silver miners. These investment vehicles started the third quarter on weak footing, like silver, but ended with far superior gains.At one time, silver investors looking for an alternative to outright metal purchases had little choice other than buying individual mining stocks. Today, investors have the option of investing in a miner ETF, which conveniently bundles companies and sells shares in the group. But most people looking for alternatives flock instead to physically-backed ETFs. These investment vehicles provide exposure to metal prices, but do not require investors to share mining companies' risks — a highly attractive proposition for many market participants. The largest silver ETF, the iShares Silver Trust (ARCA: SLV), has a market cap of $10.95 billion, whereas the largest silver miner ETF, Global X Silver Miners (ARCA: SIL), has a market cap of $377 million. But the third quarter proved that taking the route less traveled can be considerably more rewarding. In Q3, silver miner ETFs outperformed metal prices and physically-backed ETFs. As of October 1, SLV had three-month gains slightly over 26 percent. SIL's gains for the period were nearly 35 percent and iShares Global Silver Miners (ARCA:SLVP) was up over 34 percent. This year, many investors considered silver mining stocks extremely undervalued. Whether investors would return to snap up mining shares and what would prompt them to do so have been long-running questions.