Which of these companies is worth a closer look? Is one a buy and the other worth ignoring? Stock price and recent movement can't tell you that, but looking at a stock's forward price-to-earnings ratio can help you determine if it is fairly valued. Arm's forward P/E sits at a staggering 119, one of the highest in its sector. Tenable's forward P/E is less than a third of that at 36. What do these two companies do? In addition to licensing IP cores for central processing units (CPUs), Arm has a smaller graphi ...