Nvidia\u2019s online game-streaming service will launch next week after a year-long beta testing period, but it will only be available to owners of the company\u2019s Shield tablet and handheld gaming console.The Nvidia GRID cloud gaming service will first be available in the U.S. as a free preview and the company is not saying whether it will become a paid service. It could launch in Europe as early as next month.Nvidia\u2019s service will compete with Sony\u2019s PlayStation Now game-streaming service, which is still in beta and works with Sony\u2019s TVs and gaming consoles. But Nvidia is promising a better gaming experience, with titles streaming out at 720p resolution and 60 frames per second.The service will start with 20 streaming games, including \u201cBatman: Arkham City\u201d and \u201cBorderlands 2,\u201d, with more titles added later. Nvidia hopes the service will attract more buyers to the Shield tablet, which starts at US$299 with 16GB of storage. The tablet will be upgraded to Android 5.0 in coming weeks.The streaming service takes advantage of specific hardware and graphics features in Shield devices. It won\u2019t work on mobile devices from other companies, though that could change in the future, said Andrew Fear, senior product manager for GRID cloud computing at Nvidia.\u201cThere\u2019s technically nothing stopping it from working on any device,\u201d Fear said.The service initially won\u2019t work on PCs either. But Nvidia could extend the service to desktops and laptops with its GeForce graphics cards.Nvidia is best known for its graphics cards, but started selling Shield devices\u2014which use its graphics and mobile CPU chipsets\u2014to expand its presence in gaming. Nvidia\u2019s streaming service is based on PC gaming, which the company says is better than console gaming due to the ability to easily change and upgrade hardware. Nvidia also competes with Advanced Micro Devices, whose graphics technologies are used in PCs and all the popular gaming consoles.Streaming games will load in a matter of seconds and the service runs off servers powered by Amazon\u2019s cloud infrastructure. Fear said the infrastructure is already in place to deploy the service in the Asia-Pacific region, but he did not share specific launch dates.\u201cWe\u2019ve been working to deploy thousands of servers in Amazon\u2019s cloud,\u201d Fear said. \u201cWe\u2019re leveraging that infrastructure to deploy this.\u201dThe online gaming service was in beta for more than a year through servers in California, with users connected worldwide. After it was clear that users far away from California experienced no latency, Nvidia decided the servers were ready to take on more gamers and that there was sufficient bandwidth to handle the service.The games are processed and streamed from Nvidia\u2019s GRID servers packed with GPUs based on the Kepler architecture. Nvidia made tweaks in servers before the service was launched to reduce latency and ensure gaming quality remained consistent, Fear said.Online gaming is much different than a streaming audio service or video service as more feedback is sent from a client device to the server. Special effects and graphics are encoded and packaged in the remote server and then sent to the Shield tablet, which decodes the graphics. As a result, more bandwidth is needed, but encoding and decoding at the server and client sides helps reduce latency.\u201cCloud, remote graphics is an entirely different mind set than local gaming,\u201d Fear said.Delivering games over the cloud is also different than playing games locally. On PCs, the GPUs can be adjusted to change the frames per second. But on cloud servers, the GPUs are running at a consistent frame rate, which if disturbed, could hurt the quality of visuals.\u201cFor us in the cloud, we have to be able to stream and render the game always at 60 frames per second. If we go below it, we\u2019re going to get a visual stutter because we weren\u2019t able to render a frame at the time the encoder was trying to encode it at 60 frames per second,\u201d Fear said.Nvidia is recommending that the service not be used over LTE connections. It runs best over Wi-Fi routers that support the 5GHz spectrum.