Thank you, Laura, and good afternoon to all those listening in today. We had a solid first quarter. Revenue was in line with our expectations at $1.27 billion, down 23% year-over-year. Ryzen and EPYC processor and data center GPU revenue more than doubled year-over-year helping expand gross margin by 5 percentage points, and partially offsetting graphics channel softness and lower semi-custom revenue.
Looking at our Computing and Graphics segment, revenue declined year-over-year as higher client processor sales were offset by lower graphics sales to the channel. Client processor sales increased by a strong double-digit percentage from the year-ago period, as unit shipments increased significantly and our new products drove a higher client ASP.
As a result, we believe we gained unit market share for the sixth straight quarter. In the desktop channel, demand for our highest-end Ryzen 7 and Ryzen 5 CPUs was strong, with sales increasing sequentially and outperforming seasonality. Ryzen mobile processor adoption continues to accelerate. Acer, Asus, Dell, HP, Lenovo, and other OEMs have launched more than a dozen new Ryzen mobile notebooks so far in 2019, helping us deliver our fifth straight quarter of year-over-year mobile processor growth.
Our customers are on track to increase the number of Ryzen notebook models by more than 50% from 2018. The majority of these new systems are planned to launch in the second quarter in advance of the seasonally stronger second half of the year. In Graphics, revenue decreased year-over-year driven largely by lower channel sales, partially offset by a significant increase in data center GPU sales. Radeon Vega GPU shipments grew by a strong double-digit percentage both year-over-year and sequentially based on increased adoption across OEM, gaming, and data center customers. Apple introduced two new iMac systems featuring upgraded Radeon Pro Vega GPUs that deliver up to 80% faster graphics performance than the previous generation. We believe we made good progress improving channel inventory levels. Sell-through accelerated sequentially driven by sales of both our mainstream Radeon RX GPUs and new high-end Radeon VII gaming GPUs.
We are well-positioned to grow GPU revenue in the second quarter and through the second half of the year as we expect to introduce our first 7-nanometer Navi gaming GPUs in the third quarter. We delivered another quarter of strong data center GPU sales based on increased adoption across large customers.
Our progress was highlighted by Google's announcement that they selected high-performance Radeon GPUs and AMD's software development tools to power their upcoming Stadia game streaming platform. Stadia is a great example of how we are extending the depth and breadth of our data center customer engagements.
We are seeing growing customer interest in our differentiated platforms for game streaming, machine learning, and HPC workloads that combine our high-performance GPUs with open source software tools.
Turning to our Enterprise, Embedded, and Semi-custom segment, revenue decreased from a year ago as expected due to lower Semi-custom revenue as we entered the seventh year of the current game console cycle.
Our Semi-custom business model continues to play an important role in our long-term growth as our strong IP portfolio enables the industry's biggest brands to create differentiated solutions. The latest example is Sony.
We are honored that Sony has selected a custom AMD SoC based on our Zen 2 CPU and Navi GPU architectures to power its next-generation PlayStation console.
Our server CPU revenue grew significantly from the year ago period, as EPYC processor adoption across cloud, HPC, and Enterprise customers continued to grow. Overall, in the data center, our CPU and GPU sales accounted for a mid-teens percentage of quarterly revenue.
Our work with cloud leader, Amazon, continues to expand as they rolled out AMD-based offerings to additional regions and launched three new EPYC processor-powered EC2 instance families, including the first T3 Series Instance. Growing HPC and regional cloud service provider deployments resulted in EPYC processor channel sales increasing sequentially. In the Enterprise, we added dozens of new customers across the aerospace, health care, automotive, and telecom industries based on the superior performance of EPYC processors in big data and general-purpose virtualized workloads.
Turning to our next-generation Rome processor, we made excellent progress in the quarter achieving key production milestones with our largest OEM and cloud customers. We're very excited about the performance of Rome, which is on track to deliver four times the floating point performance and double the compute performance per socket compared to our current generation EPYC processors.
We are on track to begin Rome production shipments in the second quarter to support a third quarter launch. In summary, I am pleased with our first quarter financial results based on the strong execution engine we have built across the company. Tomorrow is an important day in AMD's history as we celebrate our 50th anniversary. This is a significant milestone for any company, but especially significant for a technology company. 2019 is arguably the most important year in our history, as the $75 billion market for high-performance Computing and Graphics products has never been larger, and our product portfolio has never been stronger.
We are right where we plan to be with our multiyear roadmap, including our upcoming 7-nanometer Ryzen, Radeon, and EPYC processors that can drive our next wave of revenue growth and share gains. We remain confident in our ability to continue delivering on our ambitious leadership roadmap for the PC, gaming, and datacenter markets.
Now, I'd like to turn the call over to Devinder to provide some additional color on our first quarter financial performance. Devinder?