Image source: NVIDIA.

What: Shares of NVIDIA (NVDA 3.65%) rose 31.5% in May 2016, according to data from S&P Global Market Intelligence. The company published a fantastic first-quarter report, and then kept the pedal to the metal with a steady stream of product news.

So what: In the first quarter, NVIDIA's sales rose 14% year over year while GAAP earnings increased by 46%. Both results were significantly better than Wall Street's projections. That's both surprising and encouraging, given that the company is in the midst of rolling out a brand new processor architecture. The new Pascal platform is not yet generating sales, but older products proved attractive enough to carry NVIDIA's top and bottom lines.

Now what: Archrival Advanced Micro Devices (AMD 2.44%) is also introducing a new graphics platform (alongside new CPU architectures overall). The two traditional graphics powerhouses have turned their sights on new markets for those product lines, targeting supercomputing and data center operations more than gaming cards and professional graphics.

Both of these refreshed graphics architectures sports lower power consumption and higher performance, all at reduced price points thanks to better manufacturing processes. For now, both AMD and NVIDIA shares are rising on the promise of upcoming adrenaline shots from the revived rivalry. We'll have to wait and see which competitor takes the crown in head-to-head comparisons and buyer choices.

Expect further volatility in the months and quarters ahead. There's no telling yet whether NVIDIA or AMD will move up or down -- in tandem or in opposite directions.