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

What: Shares of NVIDIA (NVDA 5.48%) gained slightly this morning after Susquehanna upgraded the graphics chipmaker from negative to neutral.

So what: Along with the upgrade, analyst Chris Caso boosted his price target to $14 (from $10.50), representing about 11% worth of downside to yesterday's close. While Caso isn't exactly bullish on NVIDIA's appreciation prospects, he thinks that better graphics processing unit, or GPU, trends could stabilize the stock's risk going forward.

Now what: Susquehanna thinks that NVIDIA's risk/reward trade-off, although still not attractive, is certainly improving. "Our most recent checks have noted an improved tone within NVDA's GPU business, mainly due to product shortages by AMD (AMD 2.77%) that are limiting the competitive pressure," noted Caso. "On Tegra, we still hold low expectations for this business, but after a year of estimate reductions, Street estimates are down sharply as well." When you couple those improved trends with NVIDIA's reasonable forward P/E of 20, I'd agree that stock is at least worth looking into.