In the previous article I looked at the role the CPU plays in how well our software performs.

The next important component is the graphics processing unit, or GPU. 3DM CalibCam and DTM Generator don’t really care what GPU you use, but 3DM Analyst relies on it very heavily for the 3D View, and being able to view full colour stereo in the Stereo View depends on the GPU supporting it.

GPU Vendors

There are really only two contenders at the moment: NVIDIA and ATI. (ATI was purchased a few years ago by Intel’s CPU rival, AMD, so you’ll often see ATI cards branded as AMD instead. Apparently AMD plans to retire the ATI brand name soon.)

Intel makes GPUs but these should be avoided — not only because they are much slower, but also because they lack the features of the other two vendors’ products and implement the features they do support rather poorly. (They even tell the application they support features that they apparently don’t because when the software tries to use them, either nothing appears onscreen or (depending on the feature) the texture turns white. This is why we have the option in the software to disable more advanced features rather than simply using those features if the graphics card reports they are available!)

NVIDIA used to have a big advantage in terms of driver quality and the robustness of their OpenGL implementation (the interface that our software uses to talk to the graphics card), but that has narrowed quite a bit in the last couple of years. ATI’s drivers still have the odd serious bug or limitation but we have now identified all the ones that affect our software and our software knows how to work-around them so it’s not an issue for the end user. We also use both NVIDIA and ATI in-house so the software is always tested on both of those.

Performance-wise they are remarkably similar as well. For truly impressive performance we’re happy to recommend either the ATI HD 5xxx series (“Evergreen“) or the NVIDIA GeForce GTX 4xx series (“Fermi“). Buying a card with at least 512 MB of video memory will allow more DTMs to be loaded into the 3D View at once as well, making it easier to map structures across larger areas like that shown by the video below from our YouTube channel:

(Change the resolution from 360p to 480p at the bottom right to improve video quality.)

Note that in this case we can actually map across time as well as space, because in real life only one round was ever visible at one time!

Anandtech normally have good GPU reviews.

If you’re buying a notebook, the following list may be helpful in judging the relative performance of the notebook-specific graphics chips:

Note how well-mixed the two vendor’s products are in the list, and how far down you have to go to find something that isn’t from NVIDIA or ATI!

It’s also much better to have discrete video/graphics memory if possible.

Desktop or Workstation?

Unlike CPUs, choosing a desktop or workstation graphics card actually does make a difference with our software — primarily because the vendors have decided that “stereo viewing in a window” is a workstation-class feature. Therefore, if you want to be able to view stereo in full colour (like in the cinemas with modern 3D movies or at home with “3DTV”) then you’ll need a workstation-class graphics card (and stereo display hardware — a topic for another article). If you don’t care about full colour stereo and are happy with mapping using the 3D View, then a consumer-level desktop graphics card is much better value for money.

NVIDIA call their consumer graphics chips “GeForce” and their workstation equivalents “Quadro”. The chips themselves are usually the same but they normally disable the workstation-only functionality in the GeForce versions either in the driver or in the firmware on the graphics card. (Because of this, they can often be re-enabled using hacks downloaded from the Internet, but these don’t always work.)

The functionality that they disable for consumers is the functionality that they think “professional” users will need but consumers playing games won’t miss, like the aforementioned full colour stereo in a window. The other feature they disable that our software can benefit from is hardware antialiased line drawing, so the triangular mesh without texture in the 3D View runs slower on a GeForce than it does on a Quadro. (In practice, however, the triangular mesh without texture speed isn’t very important because (a) it’s generally fast enough anyway, and (b) most people turn on texturing, in which case it runs faster because that’s what games need.)

If you look at the notes in the Wikipedia entry on Quadro it will tell you which GeForce the Quadro in question is equivalent to. The Quadro FX 5800, for example, which costs over $5,000, is the same chip as the GeForce GTX 285, which isn’t even available here anymore but used to cost about 1/10 as much (albeit with less onboard video RAM). Both have about the same 3D View performance as a $400 ATI Radeon HD 5850. If you don’t intend to use stereo, therefore, the consumer-level graphics cards are a much better option.

ATI also have workstation-class graphics cards, which they call “Fire GL”. The consumer-grade equivalents are called “Radeon”. I have never used Fire GL cards so I can’t comment on how well they work and how good the stereo support is, but the reviews I’ve read have been positive. Unlike NVIDIA, ATI don’t seem to use wireframe performance as a distinguishing characteristic of workstation-class GPUs — Radeons are noticably faster at line drawing than GeForces are.


If you need full-colour stereo display, you’ll need to pay extra for a workstation graphics card (Quadro or Fire GL) — otherwise you can save a lot of money by using the consumer-grade equivalents, the GeForce and Radeon.

The NVIDIA and ATI/AMD GPUs are by far the best on the market today.

512 MB or more of video RAM is useful if you want to be able to load up multiple, large DTMs at once in the 3D View.

Price/performance considerations are similar to those in the previous article on CPUs, except this time rather than affecting DTM generation speed, etc., the graphics card’s performance affects how smoothly you can manipulate the 3D View, how much data you can load at once, and whether or not you can use full colour stereo in the Stereo View.