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Radeon HD 4790 vs Radeon HD 4870 1GB
Intro
The Radeon HD 4790 makes use of a 55 nm design. AMD has set the core frequency at 600 MHz. The GDDR5 RAM is set to run at a frequency of 800 MHz on this particular model. It features 640(128x5) SPUs as well as 32 Texture Address Units and 16 Rasterization Operator Units.Compare all of that to the Radeon HD 4870 1GB, which features core clock speeds of 750 MHz on the GPU, and 900 MHz on the 1024 MB of GDDR5 RAM. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 ROPs.
Power Usage and Theoretical Benchmarks
Memory Bandwidth
Theoretically speaking, the Radeon HD 4870 1GB is 13% faster than the Radeon HD 4790 overall, because of its greater bandwidth. (explain)
| Radeon HD 4870 1GB |
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115200 MB/sec |
| Radeon HD 4790 |
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102400 MB/sec |
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Texel Rate
The Radeon HD 4870 1GB should be much (more or less 56%) faster with regards to texture filtering than the Radeon HD 4790. (explain)| Radeon HD 4870 1GB |
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30000 Mtexels/sec |
| Radeon HD 4790 |
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19200 Mtexels/sec |
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Pixel Rate
The Radeon HD 4870 1GB should be much (about 25%) better at FSAA than the Radeon HD 4790, and should be capable of handling higher screen resolutions without slowing down too much. (explain)| Radeon HD 4870 1GB |
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12000 Mpixels/sec |
| Radeon HD 4790 |
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9600 Mpixels/sec |
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Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.
Price Comparison
Radeon HD 4790Amazon.com
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Radeon HD 4870 1GBAmazon.com
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Please note that the price comparisons are based on search keywords - sometimes it might show cards with very similar names that are not exactly the same as the one chosen in the comparison. We do try to filter out the wrong results as best we can, though.
Specifications
| Model | Radeon HD 4790 | Radeon HD 4870 1GB |
|---|---|---|
| Manufacturer | AMD | AMD |
| Year | 2009 | Jun 25, 2008 |
| Code Name | RV790 | RV770 XT |
| Memory | 512 MB | 1024 MB |
| Core Speed | 600 MHz | 750 MHz |
| Memory Speed | 3200 MHz | 3600 MHz |
| Power (Max TDP) | (Unknown) watts | 150 watts |
| Bandwidth | 102400 MB/sec | 115200 MB/sec |
| Texel Rate | 19200 Mtexels/sec | 30000 Mtexels/sec |
| Pixel Rate | 9600 Mpixels/sec | 12000 Mpixels/sec |
| Unified Shaders | 640(128x5) | 800(160x5) |
| Texture Mapping Units | 32 | 40 |
| Render Output Units | 16 | 16 |
| Bus Type | GDDR5 | GDDR5 |
| Bus Width | 256-bit | 256-bit |
| Fab Process | 55 nm | 55 nm |
| Transistors | 959 million | 956 million |
| Bus | PCIe 2.0 x16 | PCIe 2.0 x16 |
| DirectX Version | DirectX 10.1 | DirectX 10.1 |
| OpenGL Version | OpenGL 3.0 | OpenGL 3.0 |
Memory Bandwidth: Bandwidth is the maximum amount of information (counted in megabytes per second) that can be moved past the external memory interface in one second. The number is calculated by multiplying the card's interface width by the speed of its memory. If it uses DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The better the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.
Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly write to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.
Radeon HD 4790Amazon.com
Check prices at:
|
Radeon HD 4870 1GBAmazon.com
Check prices at:
|
Please note that the price comparisons are based on search keywords - sometimes it might show cards with very similar names that are not exactly the same as the one chosen in the comparison. We do try to filter out the wrong results as best we can, though.
|
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