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Radeon HD 3870 1GB vs Radeon HD 4850 512MB
Intro
The Radeon HD 3870 1GB has clock speeds of 775 MHz on the GPU, and 1125 MHz on the 1024 MB of GDDR4 memory. It features 320(64x5) SPUs as well as 16 Texture Address Units and 16 ROPs.Compare those specs to the Radeon HD 4850 512MB, which makes use of a 55 nm design. ATi has set the core frequency at 625 MHz. The GDDR3 RAM runs at a frequency of 993 MHz on this particular model. It features 800(160x5) SPUs along with 40 TAUs and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
| Radeon HD 3870 1GB |
|
106 Watts |
| Radeon HD 4850 512MB |
|
110 Watts |
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Memory Bandwidth
Theoretically speaking, the Radeon HD 3870 1GB should perform a small bit faster than the Radeon HD 4850 512MB overall. (explain)
| Radeon HD 3870 1GB |
|
72000 MB/sec |
| Radeon HD 4850 512MB |
|
63552 MB/sec |
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Texel Rate
The Radeon HD 4850 512MB will be much (more or less 102%) more effective at AF than the Radeon HD 3870 1GB. (explain)| Radeon HD 4850 512MB |
|
25000 Mtexels/sec |
| Radeon HD 3870 1GB |
|
12400 Mtexels/sec |
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Pixel Rate
If using a high screen resolution is important to you, then the Radeon HD 3870 1GB is the winner, and very much so. (explain)| Radeon HD 3870 1GB |
|
12400 Mpixels/sec |
| Radeon HD 4850 512MB |
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10000 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
Please note that the price comparisons are based on search keywords, and might not be the exact same card listed on this page. We have no control over the accuracy of their search results.
Radeon HD 3870 1GBAmazon.com
Other US-based stores
Amazon.co.uk
Amazon.de
Amazon.fr
|
Radeon HD 4850 512MBAmazon.com
Other US-based stores
Amazon.co.uk
Amazon.de
Amazon.fr
|
Specifications
| Model | Radeon HD 3870 1GB | Radeon HD 4850 512MB |
|---|---|---|
| Manufacturer | ATi | ATi |
| Year | Nov 19, 2007 | Jun 25, 2008 |
| Code Name | RV670 XT | RV770 PRO |
| Fab Process | 55 nm | 55 nm |
| Bus | PCIe 2.0 x16/AGP 8x | PCIe 2.0 x16 |
| Memory | 1024 MB | 512 MB |
| Core Speed | 775 MHz | 625 MHz |
| Shader Speed | N/A MHz | (N/A) MHz |
| Memory Speed | 1125 MHz | 993 MHz |
| Unified Shaders | 320(64x5) | 800(160x5) |
| Texture Mapping Units | 16 | 40 |
| Render Output Units | 16 | 16 |
| Bus Type | GDDR4 | GDDR3 |
| Bus Width | 256-bit | 256-bit |
| DirectX Version | DirectX 10.1 | DirectX 10.1 |
| OpenGL Version | OpenGL 3.0 | OpenGL 3.0 |
| Power (Max TDP) | 106 watts | 110 watts |
| Shader Model | 4.1 | 4.1 |
| Bandwidth | 72000 MB/sec | 63552 MB/sec |
| Texel Rate | 12400 Mtexels/sec | 25000 Mtexels/sec |
| Pixel Rate | 12400 Mpixels/sec | 10000 Mpixels/sec |
Memory Bandwidth: Memory bandwidth is the max amount of information (in units of megabytes per second) that can be moved over the external memory interface within a second. It is calculated by multiplying the card's bus width by its memory speed. If the card has DDR RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This figure is calculated by multiplying the total texture units of the card by the core speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per 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. Pixel rate is calculated by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.
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