The following combinations of graphics hardware and operating systems are used by the developers for development of PTB-3's Screen function and therefore tested and known to work well. This doesn't exclude other similar or more advanced system configurations which likely will work equally well or maybe even better. It just happens to be the equipment that is accessible to us for development and testing. As a rule of thumb, a specific feature of a specific piece of graphics hardware that works well on MS-Windows will likely work equally well on GNU/Linux and vice versa due to the unified drivers used for these operating systems (drivers for Windows and Linux by ATI and NVidia are derived from the same code base). This is not necessarily true for Win/Linux vs. Mac OS-X, because the OpenGL drivers for OS-X are developed by different development teams from a different code base - Apple imposes a much stricter control over their implementation of OpenGL, with different priorities wrt. feature set. This means that the same gfx hardware may expose different functionality, performance, limitations and bugs on OS-X vs. Win/Linux due to fundamental driver differences.
The summary here is just for your reference, so you can get a feeling on what to expect with specific hardware. If you buy new systems, go for the latest generation hardware of NVidia or ATI, even if you pick low end models of the latest generation! These cards provide very useful new features. Expensive high-end models differ from cheap low-end models only in raw performace, ie., drawing speed, not in functionality.
- Intel GMA 945 onboard graphics in a Dell PC under Windows XP, also tested under GNU/Linux. This card has significant limitations in timing accuracy and speed! Psychtoolbox currently can not use high precision timestamping on this card. See our Bugs page for more info. This gets only very infrequent testing.
- Intel GMA 950 of Apple MacBook. Occassionally tested. The card works reliably, timing is ok, but its a very limited card in terms of performance and features.
- NVidia Geforce2Go/GeforceMX mobile graphics chip tested under Windows 2000 and GNU/Linux in a Dell Inspiron 8000 laptop. Dual display support tested under Windows.
- NVidia Geforce4 desktop graphics chip tested under GNU/Linux.
- NVidia GeforceFX-5200 desktop graphics in a single processor PowerMac-G5 and in a standard Intel PC under GNU/Linux and Windows XP. Dual display support tested.
- ATI Radeon 9600 under Intel laptop with Windows-XP, tested only infrequently.
- Intel X3100 of Apple MacBook. Not yet tested by developers, however given its specs, the card should work reliably assuming the drivers supplied by Apple are sufficiently mature and bug free. This card and its siblings are special in the sense that feature-wise they are DirectX10 cards with support for Shader model version 4 - they can do most of what the most recent state of the art cards of NVidia and ATI can do. However, they lack any support for frame-sequential stereo, anti-aliasing and high precision HDR framebuffers and due to lack of dedicated fast VRAM memory, they only have a low computational performance. So although theoretically "state of the art" cards, they are too restricted and weak for the typical applications of such state of the art cards.
- ATI Radeon X1600 mobile chip in a Apple Intel MacBook-Pro, running OS-X 10.4.11. Dual display support tested. This is one of the main development systems for PTB.
- Nvidia Geforce 6800 mobile chip in a high end Dell Laptop under Windows XP and GNU/Linux. Dual display support tested. Tested once, worked.
- NVidia Geforce 7800 GT, tested under Windows XP and GNU/Linux. Our test platform for high performance image processing. Dual display support tested. Support for high dynamic range display devices tested. (Currently used in many experimental setups at MPI Tuebingen).
- NVidia Geforce 8600 - 8800, 9xxx or ATI Radeon HD 2000/3000 systems: These provide a couple of new interesting features, especially if you need HDR rendering or high precision framebuffers for fine control over contrast and color. Buy one of these if you have the choice!
OpenGL graphics hardware exposes its functionality via so called OpenGL extensions. Each extension defines a specific subset of functionality supported by the hardware. Specific advanced features of PTB-3 require your graphics hardware to support specific sets of OpenGL extensions. If you try to use an advanced PTB feature, PTB will probe your hardware for support of the required extension. If the extension is unsupported, PTB will either refuse use of an advanced feature or it will enable internal fallback implementations that do what you want, but at a much lower performance or precision and much higher resource requirements than if your hardware would support the extension. A list of all existing OpenGL extensions, including their full in-depth technical specification, can be found at the official OpenGL extension registry.
Different models of a specific generation of graphics hardware usually share support for a common set of extensions, but they differ in the precision, performance or efficiency with which features are supported as well as in the set of constraints that need to be fullfilled in order for the hardware efficiently to support a feature. The following websites list the specific set of extensions that are supported for specific models of graphics hardware for specific driver versions or operating system releases. They also list many interesting properties and limitations of these graphics cards. You will notice that there are separate websites for Windows/Linux and OS/X and that if you compare the resource limits, capabilities and feature sets of the same models of graphics hardware between Win/Lin and OS/X you'll sometimes find significant differences. Given that the hardware is the same, these differences are imposed by the different design and implementation of the graphics drivers and OpenGL subsystems of Windows/Linux versus OS/X.
- Delphi3D - Support on Microsoft Windows, sorted by vendor, model and driver release
- GLInfo - Support on MacOS-X, sorted by OS release, PowerPC vs. IntelMac and model
- Wikipedia has nicely written overview articles about different graphics cards and how they differ
- Tom's hardware has some overview about the best graphics cards for a given range of money you'd like to spend. (Caution: Check how recent the article is, could become outdated.)
- And an interface for quick comparison of prices. (Caution: Could be biased, use common sense!)
If you want to buy a graphics card which is an optimal tradeoff between required features for your project and cost, you'll have to match the listed requirements of PTB against the features in those databases. PTB's Screen command outputs a list of all OpenGL extensions supported by your hardware + operating system + driver at startup ("OpenGL extensions are: ...") unless you suppress it. The websites above also provide a tool called GLInfo which probes your hardware and outputs a full listing of all tested properties if you need reliable information about your hardware.
- Support for fast, efficient textures and moderately fast Offscreen windows: GL_ARB_texture_rectangle or GL_EXT_texture_rectangle or GL_NV_texture_rectangle.
- Everything on IntelMacs, everything on PowerMacs except ATI Rage, Rage 128 or Rage Pro. NVidia Geforce2 and later on Windows/Linux. Not Intel GMA 945.
- Support for fast drawing of 3D geometry in MOGL: GL_EXT_draw_range_elements.
- All OS/X hardware. Most PC hardware.
- Support for Screen('Flip', ..., clearmode) command with clearmode=1 (don't clear after Flip): At least one AUX buffer for mono displays, two AUX buffers for stereo displays.
- Well supported on OS/X on PowerPC, faulty on OS/X IntelMac, unsupported on most Windows and Linux systems, especially with ATI hardware. Alternatively if your hardware support the PTB imaging pipeline, you'll get this feature very efficiently for free.
- Support for different stereo display methods (stereomode flag in Screen('OpenWindow', ...):
- Frame sequential stereo for shutter glasses: Blue line syncing method supported on all OS/X hardware except ATI Rage and Intel GMA 950.. On Windows, only expensive professional line hardware is supported (ATI FireGL series and NVidia Quadro series). Linux can be extended in various ways to support commodity hardware in addition to the professional line hardware, and to support very special setups, e.g., high performance render clusters.
- Vertical split screen stereo (modes 2 and 3): Supported on OS/X PowerPC on all hardware. All other platforms need support for the PTB imaging pipeline for this to work.
- Dualview stereo for free fusion, cross fusion, haploscopes and dual display systems: Works on all hardware and OS, either via cheap display splitter hardware like the Matrox DualHead2Go or via dual display (dual head) graphics cards.
- Anaglyph stereo: Basic support (without automatic gain correction, desaturation or color to luminance conversion) works on all systems. Advanced anaglyph stereo with automatic color to luminance conversion, desaturation and gain correction is only supported on hardware that supports the PTB imaging pipeline.
- Other algorithms: Need basic support for PTB imaging pipeline.
- Support for full scene anti-aliasing (multisample parameter of Screen('OpenWindow', ...)): Needs GL_ARB_multisample with at least 1 multisample buffer (See constants Max Sample Buffers and Max Samples, bigger is better.
- Supported on most ATI and NVidia hardware, not supported on Intel onboard graphics, e.g., GMA 950 of MacMini, IntelMac or MacBook.
- Support for fast Offscreen windows: Needs support for basic imaging pipeline.
- Support for fast geometric display distortion correction, display hotspotting correction, color correction, clut animation: Needs support for basic imaging pipeline.
The Psychtoolbox imaging pipeline is a built-in framework for fast image processing on the graphics hardware, currently in beta stage. It allows to perform common image processing operations on image stimuli (represented as Psychtoolbox textures), to customize and extend the behavior of specific Screen drawing commands and to provide a set of fully automatic post processing operations on your final visual stimuli which may be useful for some more advanced applications. The infrastructure is integrated into PTB, but the specific operations are implemented as shader plugins, written in the OpenGL shading language (GLSL) and executed on the graphics processor itself. The imaging pipeline requires recent hardware for basic operation and mid-level to high-end hardware for the more advanced features.
Basic imaging pipeline support:
Provides the following features:
- Fast efficient support for Offscreen windows. (Implemented)
- Fast support for "don't clear after Flip" mode (dontclear=1) for the Screen('Flip') command, allows for incremental drawing of stimuli. (Implemented)
- Automatic drawing of blue sync lines for frame sequential stereo on consumer hardware. (Implemented)
- Fast support for vertical split screen stereo modes (stereomode 2 and 3). (Implemented)
- Flexible high quality Anaglyph stereo modes with automatic conversion of color stimuli into grayscale images, online color gain correction, desaturation and alternate anaglyph implementations. (Implemented)
- New stereo modes, e.g., interlaced stereo and vertically interlaced stereo for free viewing setups with lenticular lens systems. (On your request)
- Fast remapping of pixel values via lookup tables, e.g., for palette animation. (Implemented)
- Correction of inhomogenities in display intensity via application of per pixel gain values. (On your request)
- Geometric undistortion and alignment for non-rectilinear displays. (Implemented)
Minimum requirement for 2D drawing is the support for the following OpenGL extensions: GL_EXT_framebuffer_object, GL_ARB_multitexture, GL_ARB_shading_language_100, GL_ARB_shader_objects, GL_ARB_vertex_shader, GL_ARB_fragment_shader.
The following cards and later models are known to fully support these extensions: ATI Radeon 9600, NVidia GeforceFX-5200, Intel GMA-950 onboard chip of Intel based MacMinis and MacBooks under OS/X.
For 3D graphics via MOGL or OpenGL one needs these additional extensions: GL_ARB_depth_texture for depth buffer support and GL_EXT_packed_depth_stencil for stencil buffer support on some systems. Stencil buffers are unsupported on all PowerPC hardware (an OS limitation not a hardware limitation), unless you use OS-X 10.5 "Leopard" and later.
High dynamic range support:
This allows for drawing, processing and representation of images with floating point precision. Color values can exceed the normal 0-255 integer range of standard 8bpc framebuffers and one can handle images and colors with negative color components. This is useful for efficient creation of specific stimuli, e.g., fields of overlapping gabor patches and special blending operations. The final stimulus image can get automatically converted into a format suitable for special high precision display hardware, e.g., CRS Bits++, video attenuators, high dynamic range display devices.
Required extensions: A subset of GL_ARB_float_pixels, GL_APPLE_float_pixels, GL_ATI_float_pixels, GL_NV_float_pixels, GL_ATI_texture_float, GL_ARB_texture_float, GL_NV_texture_float.
At least the following graphics cards should support this according to their specification: NVidia Geforce-6000 series and ATI Radeon X800 series.
The following cards have been successfully tested for support: ATI X1600 and NVidia Geforce 7800. All later cards will support this as well.
The NVidia GeforceFX 5200 should support it, but malfunctioned on OS/X PowerPC during tests. This may be different on OS-X 10.5 Leopard, but is untested so far.
The Intel GMA 950 does not support these functions.
Advanced support for imaging pipeline:
This allows for more complex shaders and therefore for additional functionality, especially in the area of general purpose image processing:
- Support for display devices with complex output processing requirements: E.g., BrightSide Technology High Dynamic Range display.
- Support for 2D convolution, 2D FFT and other standard image processing operations.
- Support for iterative algorithms and machine vision algorithms.
The graphics hardware needs to be Shader model 3.0 (aka DirectX 9.0c, aka Windows Vista Premium ready) compliant.
Known cards that should work well: (Follow the links for detailed infos about the different models)
- NVidia Geforce 6000 and 7000 series (e.g., Geforce 6800), NVidia Geforce 8000 series and later recommended, Quadro FX 4500. PTB is tested on Geforce 7800 GTX.
- ATI Radeon X1300 and later. PTB is tested on the Mobility Radeon X1600 of the Apple MacBook-Pro.
Good luck in choosing a suitable card.