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HardNetSoft Blog
The Intel Graphics Media Accelerator, or GMA, is Intel's current line of integrated graphics processors built into various motherboard chipsets.
These integrated graphics products allow a computer to be built without a separate graphics card, which can reduce cost, power consumption and noise. They are commonly found on low-priced notebook and desktop computers as well as business computers, which do not need high levels of graphics capability. 90% of all PCs sold have integrated graphics.[1] They rely on the computer's main memory for storage, which imposes a performance penalty, as both the CPU and GPU have to access memory over the same bus.
The GMA line of GPUs replaces the earlier "Intel Extreme Graphics", and the Intel740 line, which were discrete units in the form of AGP and PCI cards. Later, Intel integrated the i740 core into the Intel 810 chipset.
The original architecture of GMA systems supported only a few functions in hardware, and relied on the host CPU to handle at least some of the graphics pipeline, further decreasing performance. However, with the introduction of Intel’s 4th generation of GMA architecture (GMA X3000) in 2006, many of the functions are now built into the hardware, providing an increase in performance. The 4th generation of GMA combines fixed function capabilities with a threaded array of programmable executions units, providing advantages to both graphics and video performance. Many of the advantages of the new GMA architecture come from the ability to flexibly switch as needed between executing graphics-related tasks or video-related tasks. While GMA performance has been widely criticized in the past as being too slow for computer games, the latest GMA generation should ease many of those concerns for the casual gamer.
Despite similarities, Intel's main series of GMA IGPs is not based on the PowerVR technology Intel licensed from Imagination Technologies. Intel used the low-power PowerVR MBX designs in chipsets supporting their XScale platform, and since the sale of XScale in 2006 has licensed the PowerVR SGX and used it in the GMA 500 IGP for use with their Atom platform.
Graphics cores
GMA 900: The GMA 900 was the first graphics core produced under Intel's Graphics Media Accelerator product name, and was incorporated in the Intel 910G, 915G, and 915Gx chipsets.
The 3D architecture of the GMA 900 was a significant upgrade from the previous Extreme 3D graphics processors. It is a 4 pixel per clock cycle design supporting DirectX 9 pixel shader model 2.0. It operates at a clock rate ranging from 160 to 333 MHz, depending on the particular chipset. At 333 MHz, it has a peak pixel fill-rate of 1332 megapixels per second. However, the architecture still lacks support for hardware transform and lighting and the similar vertex shader technologies.Like previous Intel integrated graphics parts, the GMA 900 has hardware support for MPEG-2 motion compensation, color-space conversion and DirectDraw overlay.
The processor uses different separate clock generators for display and render cores. The display unit includes a 400 MHz RAMDAC, 2 25–200 Mpixel/s serial DVO ports, and 2 display controllers. In mobile chipsets, up to 2 18-bit 25–112 MHz LVDS transmitters are included.
GMA 950: The GMA 950 is Intel's second-generation graphics core, which was also referred by Intel as 'Gen 3.5 Integrated Graphics Engine' in datasheets. It is used in the Intel 940GML, 945G, 945GU and 945GT system chipsets. The amount of video-decoding hardware has increased; VLD, iDCT, and dual video overlay windows are supposed to be handled in hardware.[2] However in a feature comparison document[3] it is noted, that VLD and iDCT are not supported until GMA 3100 (on G33 chipsets only). The maximum core clock is up to 400 MHz (on Intel 945G, 945GC, 945GZ, 945GSE), boosting pixel fill-rate to a theoretical 1600 megapixels/s.
The GMA 950 shares the same architectural weakness as the GMA 900: no hardware geometry processing. Neither basic hardware transform and lighting,[4] nor more advanced vertex shaders are handled in the GMA hardware.GMA 3000: The 946GZ, Q965, and Q963 chipsets use the GMA 3000 chip.[5][6] The GMA 3000 3D core is very different from the X3000, despite their similar names. It is based more directly on the previous generation GMA 900 and GMA 950 graphics, and belonging to the same "i915" family with them. It has pixel and vertex shaders which only support Shader Model 2.0b features, and the vertex shaders are still only software-emulated. In addition, hardware video acceleration such as hardware-based iDCT computation, ProcAmp (video stream independent color correction), and VC-1 decoding are not implemented in hardware. Of the GMA 3000-equipped chipsets, only the Q965 retains dual independent display support. The core speed is rated at 400 MHz with 1.6 Gpixel/s fill rate in datasheets, but was listed as 667 MHz core in the white paper.[7]
The memory controller can now address a maximum of 256 MB of system memory, and the integrated serial DVO ports have increased top speed to 270Mpixel/s.GMA 3100: The G31, G33, Q33 and Q35 chipsets use the GMA 3100, which is DirectX 9 capable. The 3D core is very similar to the older GMA 3000, including the lack of hardware accelerated vertex shaders.
GMA X3000: The GMA X3000 for desktop was "substantially redesigned" when compared to previous GMA iterations[8] and it is used in the Intel G965 north bridge controller.[9] The GMA X3000 was launched in July 2006.[10] X3000's underlying 3D rendering hardware is organized as a unified shader processor consisting of 8 scalar[11] The GMA X3000 supports DirectX 9.0 with vertex and pixel Shader Model 3.0 features. execution units. Each pipeline can process video, vertex, or texture operations. A central scheduler dynamically dispatches threads to pipeline resources, to maximize rendering throughput (and decrease the impact of individual pipeline stalls.) However, due to the scalar nature of the execution units, they can only process data on a single pixel component at a time.
The processor consists of different clock domains, meaning that the entire chip does not operate the same clock speed. This causes some difficulty when measuring peak throughput of its various functions. Further adding to the confusion, it is listed as 667 MHz in Intel G965 white paper, but listed as 400 MHz in Intel G965 datasheet. There are various rules that define the IGP's processing capabilities.[11]Memory controller can now address maximum 384 MB memory according to white paper, but only 256 MB in datasheet.
GMA X3100: Information: The GMA X3100 is the mobile version of the GMA X3000 used in the Intel GL960/GM965 chipsets and also in the GS965 chipset. The X3100 supports hardware transform and lighting, up to 128 programmable shader units, and up to 384 MB memory. Its display cores can run up to 333 MHz on GM965 and 320 MHz on GL960. Its render cores can run up to 500 MHz on GM965 and 400 MHz on GL960. The X3100 display unit includes a 300 MHz RAMDAC, two 25–112 MHz LVDS transmitters, 2 DVO encoders, and a TV encoder. In addition, the hardware supports DirectX 10.0,[3] Shader Model 4.0 and OpenGL 1.5.[12]
GMA X3500: GMA X3500 is an upgrade of the GMA X3000 and used in the desktop G35. The shaders support shader model 4.0 features. Architecturally, the GMA X3500 is very similar to the GMA X3000,[13] with both GMAs running at 667 MHz. The major difference between them is that the GMA X3500 supports Shader Model 4.0 and DirectX 10, whereas the earlier X3000 supports Shader Model 3.0 and DirectX 9.[13] The X3500 also adds hardware-assistance for playback of VC-1 video.
GMA X4500: The GMA X4500 and the GMA X4500HD for desktop[14] were launched in June 2008.[15] The GMA X4500 is used in the G43 chipset[16] and the GMA X4500HD is used in the G45 chipset.[14] The GMA X4500 is also used in the G41 chipset,[17][18] which was released in September 2008.
The GMA 4500MHD for laptops was launched on July 16, 2008. Featurewise, the 4500MHD is identical to its desktop cousin, the X4500HD.[citation needed] It had been previously rumored that a cost-reduced version, the GMA 4500, was to be launched in late 2008 or early 2009[19] and was to be used in the upcoming Q43 and Q45 chipsets.[17] But in practice the Q43 and Q45 Chipsets also use the GMA X4500.[20]The difference between the GMA X4500 and the GMA X4500HD is that the GMA X4500HD is capable of "full 1080p high-definition video playback, including Blu-ray disc movies",[14][21]
Like the X3500, X4500 supports DirectX 10 and Shader Model 4.0 features. Intel designed the GMA X4500 to be 200% faster than the GMA 3100 (G33 chipset) in 3DMark06 performance[22] and 70% faster than the GMA X3500 (G35 chipset).[23]
