ATI Mobility Radeon HD 4850 vs ATI Mobility Radeon HD 4830
ATI Mobility Radeon HD 4850► remove
The ATI Mobilty Radeon HD 4850 from AMD is a DirectX 10.1 upper middle-class notebook graphics adapter. Technically, the GPU is based on the desktop HD 4850 GPU but with a lower clock rate for reduced energy consumption.
The gaming performance of the ATI Mobility Radeon HD 4850 should be comparable to the desktop HD 4830 and is therefore very good at resolutions below 1080p. The high amount of shaders and the wide 256 bit bus can allow the card to run practically every DirectX 9 game in high resolutions and details. Demanding DirectX 10 games, such as Crysis, can be played with medium to high detail settings. Compared to an Nvidia GeForce GTX 260M, the HD 4850 should be a bit faster on average.
The newer Mobility HD 5850 is noticeably faster than the Mobility HD 4850 if GDDR5 graphics memory is present. If DDR3 with a smaller 128 Bit memory bus is used instead, then this would bottlebeck the 5850 to performance levels closer to that of the Mobility HD 4850.
The mobile HD 4850 core is based on the RV770 chip and features 800 stream processors (or 160 5-dimensional shader cores). These cores do the graphics work previously done by dedicated shader and pixel pipelines of older GPUs. The stream processors (also called ALUs) are grouped in five-way VLIW units. Each of the five instructions of a VLIW bundle has to be independent from the others, so the overall performance is highly dependent on driver optimizations.
The Mobility Radeon HD 4850 includes UVD 2, Avivo HD software and an onboard soundchip for 7.1 sound output over HDMI or DisplayPort. UVD 2 supports full bitstream decoding of H.264/MPEG-4 AVC and VC-1 streams by the GPU, thus reducing workload from the CPU. In addition to this, the software also supports dual video stream decoding and Picture-in Picture mode for full compliancy to the UVD BD-Live standards. Simply put, the Avivo HD technology is able to handle most video tasks and enables the GPU to decode HD videos.
AMD has claimed a current consumption of about 45-65 Watt for the cards part of the mobile HD 4850 to HD 4870 range. Still, it is unclear if this value represents the core chip alone or the entire MXM board with memory modules. We estimate that the VRAM chips would contribute about 5 Watts total to the overall energy demands of the mobile HD 4850.
Compared to the desktop ATI Radeon HD 4850, the mobile 4850 features a slower core clock and is therefore more similar to the desktop HD 4830 in terms of overall performance.
ATI Mobility Radeon HD 4830► remove
The AMD ATI Mobility Radeon HD 4830 is a slower clocked Mobility HD 4860 and based on the 40nm RV740 core. Therefore, it is similar to the desktop HD 4700 series. Because of the 40nm production process, the power consumption should be similar to the HD 4670 (according to rumors).
Instead of GDDR5 memory of the HD 4860, the 4830 can be only equipped with slow DDR3 or faster GDDR3. Therefore, the 128 Bit memory bus becomes a bottle neck and the performance is clearly degraded.
The gaming performance of the ATI Mobility Radeon HD4830 is sufficient for demanding games of 2009 in medium - high details. Our gaming benchmarks (see below) showed that a high preset in Crysis or NFS Shift resulted in barely playable framerates around 25 fps. Less demanding games, are playable in high resolution and detail settings.
The Mobility HD 4830 is based on the RV740 chip and features 640 stream processors (128 5-dimensional shader cores). These cores do the graphic work of the shader- and pixel pipelines of older GPUs. The stream processors are also called ALUs and are grouped in five-way VLIW units. Each of the five instructions of a VLIW bundle has to be independent from the others and therefore the performance depends on the optimization of the driver.
The Mobility Radeon HD 4830 includes the Avivo HD called video technology including an onboard soundchip for 7.1 sound output over HDMI or DisplayPort and the 2nd generation UVD (Unified Video Decoder). This UVD 2 supports full bitstream decoding of H.264/MPEG-4 AVC and VC-1 streams. In addition to this, it also supports dual video stream decoding and Picture-in Picture mode which makes the UVD full BD-Live compliant. Simplified, the Avivo HD technology handles all video tasks and enables the GPU to decode HD videos.
The HD4830 was replaced by the Mobility Radeon HD 5830, which features a higher shader count (800) and DirectX 11 capable shaders. Therefore, the gaming performance of the 5830 is better, but also the power consumption should be higher (same 40nm process, although more mature).
Compared to the desktop cards, the Mobility Radeon is similar to the ATI Radeon HD 4730. Still, the desktop 4730 offers a noticeable higher performance due to GDDR5 usage and higher clock speeds.
|ATI Mobility Radeon HD 4850||ATI Mobility Radeon HD 4830|
|Mobility Radeon HD 4800 Series|
|Architecture||Terascale 1||Terascale 1|
|800 -||640 -|
|Core||500 MHz||550 MHz|
|Memory||850 MHz||700 MHz|
|Bus||256 Bit||128 Bit|
|Max. Memory||1024 MB|
|DirectX||DirectX 10.1, 4.1||DirectX 10.1, 4.1|
|Transistors||956 Million||826 Million|
|Technology||55 nm||40 nm|
|Features||OpenGL 2.0, PCI-E 2.0 x16, Powerplay, DisplayPort support up to 2560x1600, HDMI support up to 1920x1080 (both with 7.1 AC3 Audio), 1x Dual-Link/Single-Link DVI, 1x Single-Link DVI Support (all display ports have to be supported by the laptop manufacturer)||Powerplay, CrossFireX support,|
|512 - 768 GFlops Computing Power|
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