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GeForce 8500 GT vs GeForce GT 640 DDR3

Intro

The GeForce 8500 GT features a clock speed of 450 MHz and a DDR2 memory speed of 400 MHz. It also makes use of a 128-bit bus, and makes use of a 80 nm design. It features 16 SPUs, 8 Texture Address Units, and 4 Raster Operation Units.

Compare all that to the GeForce GT 640 DDR3, which uses a 28 nm design. nVidia has clocked the core speed at 900 MHz. The DDR3 memory runs at a frequency of 1782 MHz on this card. It features 384 SPUs as well as 32 Texture Address Units and 16 ROPs.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8500 GT 45 Watts
GeForce GT 640 DDR3 65 Watts
Difference: 20 Watts (44%)

Memory Bandwidth

In theory, the GeForce GT 640 DDR3 should be 346% quicker than the GeForce 8500 GT in general, due to its greater bandwidth. (explain)

GeForce GT 640 DDR3 57024 MB/sec
GeForce 8500 GT 12800 MB/sec
Difference: 44224 (346%)

Texel Rate

The GeForce GT 640 DDR3 is quite a bit (about 700%) more effective at anisotropic filtering than the GeForce 8500 GT. (explain)

GeForce GT 640 DDR3 28800 Mtexels/sec
GeForce 8500 GT 3600 Mtexels/sec
Difference: 25200 (700%)

Pixel Rate

If using a high screen resolution is important to you, then the GeForce GT 640 DDR3 is a better choice, by a large margin. (explain)

GeForce GT 640 DDR3 14400 Mpixels/sec
GeForce 8500 GT 1800 Mpixels/sec
Difference: 12600 (700%)

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

GeForce 8500 GT

Amazon.com

GeForce GT 640 DDR3

Amazon.com

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 GeForce 8500 GT GeForce GT 640 DDR3
Manufacturer nVidia nVidia
Year April 2007 June 2012
Code Name G86 GK107
Fab Process 80 nm 28 nm
Bus PCIe x16, PCI, PCIe x16 2.0 PCIe 3.0 x16
Memory 512 MB 2048 MB
Core Speed 450 MHz 900 MHz
Shader Speed 900 MHz 900 MHz
Memory Speed 400 MHz (800 MHz effective) 1782 MHz (3564 MHz effective)
Unified Shaders 16 384
Texture Mapping Units 8 32
Render Output Units 4 16
Bus Type DDR2 DDR3
Bus Width 128-bit 128-bit
DirectX Version DirectX 10 DirectX 11.0
OpenGL Version OpenGL 3.0 OpenGL 4.2
Power (Max TDP) 45 watts 65 watts
Shader Model 4.0 5.0
Bandwidth 12800 MB/sec 57024 MB/sec
Texel Rate 3600 Mtexels/sec 28800 Mtexels/sec
Pixel Rate 1800 Mpixels/sec 14400 Mpixels/sec

Memory Bandwidth: Memory bandwidth is the maximum amount of data (counted in megabytes per second) that can be moved past the external memory interface in one second. It is worked out by multiplying the bus width by its memory speed. If the card has DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the 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 texture map elements (texels) that are applied per second. This figure is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number 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 filling the screen with pixels (the image). The actual pixel fill rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.

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