While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a closer look at particularly stock-shaking upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of Rambus (NASDAQ:RMBS) gained 3% on Friday after Benchmark initiated coverage on the technology company with a buy rating.

So what: Along with the bullish call, analyst Gary Mobley planted a price target of $16 on the stock, representing about 43% worth of upside to yesterday's close. So while contrarians might be turned off by Rambus' price strength in recent months, Mobley's call could reflect a growing sense on Wall Street that the company's prospects still aren't fully baked into the valuation.

Now what: According to Benchmark, Rambus' risk/reward tradeoff is rather attractive at this point. "Our investment thesis hinges on our belief Rambus will continue to forge deeper relationships with leading memory suppliers and system-on-chip companies," said Mobley. "In essence, we believe Rambus will continue to shed its reputation as a patent troll and will increasingly engage with customers as a collaborative design, IP company, similar to ARM Holdings." Of course, with the stock up about 100% from its 52-week lows and trading at a steep-ish forward P/E of 25, I'd wait for a wider margin of safety before betting on it.

Brian Pacampara has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.