CAD Tech News (#145)18 Mar, 2021 By: Cadalyst Staff
Herrera on Hardware: Graphic Drivers—Purpose-Shaped for CAD Use
Keep up to date with CAD-oriented drivers and get the power you need to drive your designs.
By Alex Herrera
Graphics drivers. We know they exist, we know we need them, and chances are, we’ve all searched for the one best suited to our system and applications. But, what exactly does a graphics driver do? What are the differences between drivers, and how might they impact your CAD workstation’s throughput and reliability for your go-to applications? This month, I’ll explain the role of the driver and how drivers for CAD-oriented graphics don’t share the same functionality, performance, or stability as their game-oriented peers.
What Does the Graphics Driver Do?
A graphics driver provides a level of abstraction and translation between the application and the supporting hardware underneath. It’s impractical for either an OS or application to know enough about the underlying hardware to program directly to it in an effective and robust way, plus an independent software developer (ISV) would not have the time or expertise to support multiple vendors and architectures that evolve over time. Instead, the application programs to an application programming interface (API), and the driver underneath that API handles some or all of the work that’s required to implement the application’s requests, such as drawing a line or polygon.
In the context of professional CAD applications, running Windows, DirectX, and OpenGL remain the primary APIs used. OpenGL is the tried-and-true, open-standard offshoot from the early days of graphics workstations, originally derived from Silicon Graphics’ workstation API, IrisGL. Microsoft created DirectX back in the 1990’s to help unify support for applications, with gaming a primary focus. Due in large part to its ability to progress rapidly under one entity — in contrast to the egalitarian group-directed OpenGL board — DirectX quickly emerged to become the dominant API on Windows. With its long legacy status, OpenGL remains relevant particularly in professional CAD applications. In fact, the standard in workstation graphics benchmarking, SPEC’s Viewperf, measures 3D performance running both APIs. In addition, other APIs do exist, such as Vulkan from industry-consortium Khronos (which also manages OpenGL). It is gaining traction in gaming environments and may well have a more significant role to play in professional spaces in the future.
CAD-oriented graphics drivers are able to process designs such as this Gooch shading drawing, unlike games-oriented drivers. (Image source: NVIDIA)
In the case of DirectX, Microsoft hands off the device-dependent work to the driver but maintains much of the work that is independent of the underlying hardware. Not tied to a specific OS, OpenGL has historically required the hardware driver to handle everything underneath the API. For what it’s worth, in the early days of visual applications, ISVs did natively “talk” to hardware via standards such as VGA and predecessors. The applications today can still directly access a GPU’s bitmapped frame buffer, but they do not take advantage of GPU acceleration.
A Chip Alone Does Not a GPU Make
We tend to think of a GPU as just the hardware entity — a chip or graphics card. It’s true, the acronym does apply to and was coined for both. Furthermore, the chips that are the engines for gaming-oriented hardware such as NVIDIA GeForce and those for professional-oriented hardware such as NVIDIA Quadro tend to be the same. With all that in mind, it’s no wonder that many users don’t understand the difference between the two products. Why should you consider a Quadro with varying price premiums, when a cheaper GeForce seems to do the same thing?
The truth is, the GPU is really a combination of the hardware and the driver, as the hardware alone represents the foundation — a platform with capabilities that are impotent if not for the driver that exposes and optimizes access to that platform. Leveraging a common investment in expensive base technology is common across industries.
Take Toyota’s Tundra and Sequoia vehicles — they share the same basic automotive platform, but they’re shaped to produce vehicles optimized for different uses. Ditto for GeForce and Quadro, and it’s the driver that does much of the shaping. Drivers are different, and those differences can be significant, especially in the case of professional applications. A Quadro driver not only uniquely exposes features in hardware, but tunes performance based on typical CAD use and takes a different strategy when it comes to balancing reliability and platform stability.
The capabilities and performance a GPU can theoretically deliver for drawing 3D graphics is irrelevant if the driver on top doesn’t expose the capability or doesn’t place its performance at a high priority. Even if the GPU chips on the respective cards are the same, it doesn't mean that it will deliver the same power for CAD. Any graphics card’s performance is only as fast as the driver allows. Gaming drivers are designed with different goals than CAD drivers. A classic example is smooth 3D lines. Games don't use them, so a consumer-class driver won’t make them run fast, and probably won't even accelerate them at all. Ditto for some CAD-relevant shading such as Gooch shading, which emulates pencil-type design sketching. Read more»
Alex Herrera is a consultant focusing on high-performance graphics and workstations.
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