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Radeon HD 4790 vs Radeon HD 4890 2GB
Intro
The Radeon HD 4790 has a core clock frequency of 600 MHz and a GDDR5 memory speed of 800 MHz. It also uses a 256-bit bus, and makes use of a 55 nm design. It features 640(128x5) SPUs, 32 TAUs, and 16 ROPs.Compare those specs to the Radeon HD 4890 2GB, which uses a 55 nm design. AMD has set the core speed at 1000 MHz. The GDDR5 RAM runs at a frequency of 975 MHz on this specific model. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Memory Bandwidth
In theory, the Radeon HD 4890 2GB should be 22% faster than the Radeon HD 4790 overall, because of its higher data rate. (explain)
| Radeon HD 4890 2GB |
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124800 MB/sec |
| Radeon HD 4790 |
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102400 MB/sec |
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Texel Rate
The Radeon HD 4890 2GB will be much (more or less 108%) more effective at AF than the Radeon HD 4790. (explain)| Radeon HD 4890 2GB |
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40000 Mtexels/sec |
| Radeon HD 4790 |
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19200 Mtexels/sec |
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Pixel Rate
The Radeon HD 4890 2GB will be quite a bit (about 67%) faster with regards to full screen anti-aliasing than the Radeon HD 4790, and also should be capable of handling higher resolutions more effectively. (explain)| Radeon HD 4890 2GB |
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16000 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 4890 2GBAmazon.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 4890 2GB |
|---|---|---|
| Manufacturer | AMD | AMD |
| Year | 2009 | Apr 2, 2009 |
| Code Name | RV790 | RV790 XT |
| Memory | 512 MB | 2048 MB |
| Core Speed | 600 MHz | 1000 MHz |
| Memory Speed | 3200 MHz | 3900 MHz |
| Power (Max TDP) | (Unknown) watts | 190 watts |
| Bandwidth | 102400 MB/sec | 124800 MB/sec |
| Texel Rate | 19200 Mtexels/sec | 40000 Mtexels/sec |
| Pixel Rate | 9600 Mpixels/sec | 16000 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 | 959 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: Memory bandwidth is the largest amount of information (in units of megabytes per second) that can be transferred across the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory speed. If the card has DDR type RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed per second. This number is worked out by multiplying the total texture units by the core clock speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.
Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.
Radeon HD 4790Amazon.com
Check prices at:
|
Radeon HD 4890 2GBAmazon.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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