ATI Mobility Radeon HD 4850 vs ATI Mobility Radeon HD 4860
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 4860► remove
The Mobility HD 4860 is based off of the 40nm RV740 core with less shader cores than the Mobility HD 4850 and only a 128 bit memory bus. Because of the high core clock and GDDR5 memory, the card should still be able to perform comparatively fast.
An initial review of the desktop HD 4750 with similar specifications than the Mobility HD 4860 (but at higher clock rates) shows a score of 6000 points in the GPU test of 3DMark Vantage. According to our benchmarks, this score puts the AMD card above the GeForce 280M.
AMD has also published a benchmark comparison between the HD 4850 and HD 4860 mobile graphics cards and showed that the 4860 was able to perform a few percentage points better in 3DMark06 under 1920x1200 pixel resolution.
At Cebit 2009, Asus showed us a 15" laptop with a Mobility Radeon HD 4860 for a hopeful launch in Q2 2009. Our press contact stated that the mobile HD 4860 may perform a bit worse than the mobile HD 4850. In the presented pre-production sample, there was an unspecified "Mobility Radeon 4500 Series" graphics card installed that scored only a bit above 2000 points in 3DMark06.
The features of the HD 4860 should be comparable to the HD 4850 with regards to Avivo HD video functionality, Powerplay and the integrated sound controller for HDMI output.
|ATI Mobility Radeon HD 4850||ATI Mobility Radeon HD 4860|
|Mobility Radeon HD 4800 Series|
|Architecture||Terascale 1||Terascale 1|
|800 -||640 -|
|Core||500 MHz||650 MHz|
|Memory||850 MHz||1000 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,|
|832 GFlops Computing Power|
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