Advanced Micro Devices (AMD -2.65%) transformation from also-ran chip company to dominant designer of next-gen computing hardware is complete. With an extensive suite of high-end products addressing all major needs from consumer to cloud, AMD is growing at a fast clip, generating a healthy profit margin, and further investing in itself so it can continue gobbling up market share in the industry.

Second-quarter 2021 earnings were proof of this. With a big upgrade in its full-year outlook and the global chip shortage expected to last into 2022, here are three reasons AMD's stock is still a buy. 

Two researchers working on semiconductors in an office.

Image source: Getty Images.

1. Extra supply equated to a sales beat

AMD reported revenue of $3.85 billion in Q2, up 99% from a year ago and an acceleration from the 93% pace set in Q1. To be fair, the spring quarter was lapping the period during the first economic lockdowns in 2020 when sales were sparse. However, let's not take too much away from AMD. Semiconductor industry titan Intel was lapping a poor showing from a year ago too, but recently reported flat revenue in its Q2 2021.

The $3.85 billion in sales actually beat CEO Dr. Lisa Su and the company's guidance provided a few months ago by $150 million. Su attributed part of the outperformance to AMD's ability to coax some extra supply from its chip fabrication partners during the last three-month period. More supply is expected to come online during the second half of 2021, but the global chip shortage will likely continue into 2022.

Nevertheless, AMD's Q2 beat and further advance on the supply side led Su and the top team to raise its outlook for full-year 2021 sales growth. Revenue is now expected to be up approximately 60% from 2020, compared to previous guidance for 50% growth.

2. Years of market share gains could lie ahead

The former underdog now has an advanced lineup of chips -- on many fronts, more advanced than the flagging Intel -- and as a result, reported yet another quarter of growth across its entire product line. 

During Q2, AMD said half of the world's newest and fastest supercomputers were powered by its EPYC data center CPUs (central processing units). Alphabet's Google Cloud also announced big leaps in price-to-performance using EPYC CPUs versus peers, no doubt helping lead to the increased adoption of the chips in cloud computing and data centers. And on the consumer chip front, Tesla chose AMD hardware to power the infotainment system in the latest Model S and Model X.  

These market share gains could continue for some time at AMD. The company's next-gen products utilizing 5-nanometer architecture (the smallest and highest-performing chips) are coming in 2022 -- well ahead of the product roadmap at rival Intel.

3. AMD is now a highly profitable firm

As AMD's technology has improved and sales have gained, its profitability profile has also been significantly raised. In Q2 2021, operating profit margin was 22% -- helping it break from the below-industry average, single-digit percentage operating margin it was stuck in for years. Free cash flow generated in the quarter was $888 million.

The implications of this are significant. AMD can now comfortably invest in itself from cash it generates, and go shopping with the excess when an opportunity arises. Take Xilinx (XLNX), for example. The acquisition of the leading field-programmable gate array (FPGA) company will close by the end of this year and open up yet another front on which AMD can attack Intel. Adding Xilinx to the mix will also further boost AMD's profit margin and research and development capabilities. This is a great match for the company and will position it for many more years of expansion. 

Investor takeaway

AMD's stock now trades for 46 times trailing-12-month free cash flow. Considering the growth it expects to generate on its own and the looming addition of Xilinx, shares look like a long-term value right now.