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GeForce 9800 GT 1GB vs GeForce GT 640 DDR3
Intro
The GeForce 9800 GT 1GB features a clock speed of 600 MHz and a GDDR3 memory frequency of 900 MHz. It also uses a 256-bit memory bus, and makes use of a 65/55 nm design. It is comprised of 112 SPUs, 56 TAUs, and 16 ROPs.Compare those specifications to the GeForce GT 640 DDR3, which makes use of a 28 nm design. nVidia has clocked the core speed at 900 MHz. The DDR3 memory works at a frequency of 1782 MHz on this card. It features 384 SPUs as well as 32 TAUs and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
| GeForce GT 640 DDR3 |
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65 Watts |
| GeForce 9800 GT 1GB |
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105 Watts |
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Memory Bandwidth
The GeForce 9800 GT 1GB should theoretically perform a bit faster than the GeForce GT 640 DDR3 overall. (explain)
| GeForce 9800 GT 1GB |
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57600 MB/sec |
| GeForce GT 640 DDR3 |
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57024 MB/sec |
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Texel Rate
The GeForce 9800 GT 1GB should be a small bit (approximately 17%) faster with regards to anisotropic filtering than the GeForce GT 640 DDR3. (explain)| GeForce 9800 GT 1GB |
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33600 Mtexels/sec |
| GeForce GT 640 DDR3 |
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28800 Mtexels/sec |
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Pixel Rate
If running with a high screen resolution is important to you, then the GeForce GT 640 DDR3 is the winner, and very much so. (explain)| GeForce GT 640 DDR3 |
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14400 Mpixels/sec |
| GeForce 9800 GT 1GB |
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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
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.
GeForce 9800 GT 1GBAmazon.com
Other US-based stores
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GeForce GT 640 DDR3Amazon.com
Other US-based stores
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Specifications
| Model | GeForce 9800 GT 1GB | GeForce GT 640 DDR3 |
|---|---|---|
| Manufacturer | nVidia | nVidia |
| Year | July 2008 | June 2012 |
| Code Name | G92a/b | GK107 |
| Fab Process | 65/55 nm | 28 nm |
| Bus | PCIe x16 2.0 | PCIe 3.0 x16 |
| Memory | 1024 MB | 2048 MB |
| Core Speed | 600 MHz | 900 MHz |
| Shader Speed | 1500 MHz | 900 MHz |
| Memory Speed | 900 MHz (1800 MHz effective) | 1782 MHz (3564 MHz effective) |
| Unified Shaders | 112 | 384 |
| Texture Mapping Units | 56 | 32 |
| Render Output Units | 16 | 16 |
| Bus Type | GDDR3 | DDR3 |
| Bus Width | 256-bit | 128-bit |
| DirectX Version | DirectX 10 | DirectX 11.1 |
| OpenGL Version | OpenGL 3.0 | OpenGL 4.2 |
| Power (Max TDP) | 105 watts | 65 watts |
| Shader Model | 4.0 | 5.0 |
| Bandwidth | 57600 MB/sec | 57024 MB/sec |
| Texel Rate | 33600 Mtexels/sec | 28800 Mtexels/sec |
| Pixel Rate | 9600 Mpixels/sec | 14400 Mpixels/sec |
Memory Bandwidth: Memory bandwidth is the maximum amount of data (measured in MB per second) that can be transported past the external memory interface in one second. The number is calculated by multiplying the card's interface width by its memory clock speed. If the card has DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This figure is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.
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