- 2GB of GDDR5 memory
- 750MHz core clock
- 900Mhz Memory clock 3.6GHz effective memory clock
- 256-bit memory interface
- Vapor-X cooling
- DirectX 10.1
- 24x Custom Filter Anti-Aliasing (CFAA)
- PCI Express 2.0 support
- 2-slots
- Dynamic Geometry Acceleration
- Game Physics processing capability
- AVIVO
- Power Play
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Brand Name | Sapphire
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Part Number | Vapor-X HD 4870 2G GDDR5
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Graphics Chip | RV 770 Pro
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Core clock | 750MHz
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Shader Clock | 750MHz
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SPs | 800
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Fabrication Process | 55nm
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Transistors | 968 Million
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Memory clock | 3600MHz effective
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Memory bus | 256-bit
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Memory bandwidth | 115.2GB/second
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Memory Size | 2048MB
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ROPs | 32
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Texture Filtering Units | 80
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Texture Filtering Rate | 2x 36.9 Gigatexels/second
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HDCP Support | Yes
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HDMI Support | Yes
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Connectors | Dual Link DVI, HDMI, VGA, TV-Out
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RAMDACs | 400MHz
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Bus PCI Express | 2.0
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Form Factor | ATX
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Power Connectors | 2x 6-pin power
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ATI released the RV770 Pro chip which is the heart of the Radeon HD 4870 last year to combat NVIDIA's GeForce GTX260 card. The chip has 968 million transistors and is manufactured on a 55nm process at TSMC's fabrication labs. The chip has 800 Stream Processors and is capable of 1.2 TeraFLOPs of computing power all on a 260mm2 die package.
Sapphire logo
Sapphire has included 2GB of memory on this card which is quadruple what the original HD 4870 had and double the memory found on the HD 4870 1GB video cards. The HD 4870 uses GDDR5 memory which effectively doubles the memory bandwidth found on cards using GDDR3 memory. The memory runs at 900MHz, meaning that the effective memory bandwidth is 115.2GB/second.
The key feature differentiating ATI cards from NVIDIA cards is the ability to do DirectX 10.1 features as image quality and performance between the two companies' equivalent cards is nearly the same. DirectX 10.1 is the intermediate step between DirectX 10.0 which NVIDIA fully supports and the next DirectX, DirectX 11. DX 10.1 features 4x MSAA support as a requirement, support for parallel cube mapping, Shader Model 4.1, and 32-bit floating point operations. NVIDIA, on the other hand has only released support on their mobile chips.
Vapor-X cooling is based on the same principles as heatpipe technology. The liquid coolant is vaporized on a hot surface, i.e. the heatpipe with the resulting vapor condensed on a cold surface then the liquid is returned to the hot surface. In this case the heatpipe is a flat surface that is in contact with the graphics chip instead of a round pipe. Covering the heat plate is a heatsink and fan that effectively cools the whole graphics card. This should prove to be an interesting cooling solution and run cooler than the normal graphics card with this chip.
