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Radeon HD 4790 vs Radeon HD 4890 2GB
Intro
The Radeon HD 4790 has a clock speed of 600 MHz and a GDDR5 memory frequency of 800 MHz. It also makes use of a 256-bit memory bus, and makes use of a 55 nm design. It is made up of 640(128x5) SPUs, 32 Texture Address Units, and 16 Raster Operation Units.Compare that to the Radeon HD 4890 2GB, which has core speeds of 1000 MHz on the GPU, and 975 MHz on the 2048 MB of GDDR5 memory. It features 800(160x5) SPUs along with 40 Texture Address Units and 16 ROPs.
Power Usage and Theoretical Benchmarks
Memory Bandwidth
The Radeon HD 4890 2GB, in theory, should be much faster than the Radeon HD 4790 overall. (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%) better at anisotropic filtering 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
If running with a high screen resolution is important to you, then the Radeon HD 4890 2GB is a better choice, by a large margin. (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: Bandwidth is the max amount of data (counted in MB per second) that can be moved across the external memory interface in one second. It's calculated by multiplying the card's interface width by its memory speed. If it uses DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This is calculated by multiplying the total number of texture units by the core speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.
Pixel Rate: Pixel rate is the most pixels the video card can possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.
Radeon HD 4790Amazon.com
Check prices at:
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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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