Thank you, Lisa, and good afternoon, everyone. 2017 was a pivotal year for AMD. We grew annual revenue 25% over 2016 with revenue growth increasing every quarter on a year-over-year basis, culminating in growth of 34% in the fourth quarter of 2017. In addition, we expanded gross margin by 3 percentage points and achieved GAAP profitability for the year. Computing and Graphics annual revenue grew 54% in 2017, while Enterprise, Embedded and Semi-custom annual revenue was flat. Both segments posted operating profits for the year, and it is particularly noteworthy that the Computing and Graphics segment was profitable for the first time in 6 years.
Based on the overall strength of the business and our new high-performance products, we have set a strong foundation for achieving our long-term financial model. Now let me turn to our results for the fourth quarter of 2017. Total revenue of $1.48 billion grew 34% year-over-year, driven by strong Radeon and Ryzen product demand. On a sequential basis, revenue declined 10%, better than expected, driven by seasonally lower semi-custom sales and partially offset by strong demand for new CPU and GPU products. Gross margin was 35%, expanding 3 percentage points year-over-year, primarily due to a larger portion of revenue coming from Computing and Graphics, driven by our new high-performance products.
Operating expenses were $412 million compared to $357 million a year ago. The increase was driven primarily by R&D and new product go-to-market investments, partially offset by an R&D credit related to a technology development agreement. Operating income was $103 million, up significantly from $26 million a year ago, and operating margin was 7%, up from 2% a year ago. AMD received a onetime tax credit of $18 million as a result of U.S. corporate tax reform, which resulted in a net tax benefit of $8 million in the quarter. Net income was $88 million, or diluted earnings per share of $0.08, as compared to a net loss of $8 million or $0.01 per share in the year-ago period. Adjusted EBITDA was $142 million compared to $60 million a year ago, and adjusted EBITDA for 2017 was $445 million.
Now turning to fourth quarter business segment results. Computing and Graphics segment revenue was $958 million, up 60% year-over-year due to strong sales of our Radeon graphics and Ryzen desktop processors. Computing and Graphics segment operating income was $85 million compared to a loss of $21 million a year ago. The strong improvement was due to higher revenue. Enterprise, Embedded and Semi-Custom revenue was $522 million, up 3% year-over-year, driven by server revenue. Operating income was $19 million, down from $47 million a year ago, primarily due to the absence of a licensing gain and ongoing R&D investments, partially offset by the benefit from a richer product mix. Turning to the balance sheet.
Our cash and cash equivalents totaled $1.18 billion at the end of the quarter, up from $879 million in Q3 due to significantly higher cash flow from operations. Inventory was $739 million, down slightly from the prior year and down 7% from the prior quarter.
Total principal debt, including our secured revolving line of credit, was $1.7 billion. In the fourth quarter, we deployed cash to repurchase $38 million of long-term principal debt resulting in a total reduction of long-term debt of $138 million in 2017. Our gross leverage ratio has improvement from 10x in 2016 to 3.8x at the end of 2017.
Free cash flow was $339 million, up sharply from $32 million in the prior quarter. Q4 is typically our strongest cash flow quarter, and for the year, free cash flow was $45 million negative due to increased working capital in support of higher revenue.
Before we turn to guidance, I want to highlight that we are adopting the new revenue recognition accounting standard effective 2018. We are adopting this standard under the full retrospective method, which we believe is most helpful to our investors. For the full year 2017, the impact of the accounting change to revenue was immaterial, and we expect the impact to be immaterial on 2018 annual revenue. For the first quarter 2018, AMD expects revenue to be approximately $1.55 billion, plus or minus $50 million, an increase of 32% year-over-year, primarily driven by the strength of the ramp of Ryzen GPU and EPYC products. For comparative purposes, under the new accounting method, Q1 '17 restated revenue was $1.18 billion and Q4 2017 restated revenue was $1.34 billion. In addition, for Q1 2018, we expect non-GAAP gross margin to be approximately 36%; non-GAAP operating expenses to be approximately $435 million or approximately 28% of revenue; non-GAAP interest expense, taxes and other to be approximately $30 million; and inventory to be up sequentially in support of higher revenue. For 2018, we expect double-digit percentage growth in annual revenue, greater than 36% non-GAAP gross margin, non-GAAP operating expenses to be approximately 28% of revenue. In addition, we expect a tax rate of approximately 10% of pretax income for 2018.
In summary, we made significant progress in 2017. We are pleased with the momentum in our business and delivered outstanding top line revenue growth, margin expansion and achieved profitability for the year. We continue to make strong progress towards our long-term target financial model, and our goal in 2018 is to deliver significant revenue growth and increase profitability as we continue to invest in our multi-generational high-performance product road maps.
With that, I'll turn it back to Laura for the question-and-answer session. Laura?