GeForce GT 220 GDDR3 vs GeForce GT 640 DDR3

Intro

Compare that to the GeForce GT 640 DDR3, which uses a 28 nm design. nVidia has set the core speed at 900 MHz. The DDR3 RAM works at a speed of 1782 MHz on this model. It features 384 SPUs as well as 32 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 220 GDDR3		58 Watts
GeForce GT 640 DDR3		65 Watts
	Difference: 7 Watts (12%)

Memory Bandwidth

The GeForce GT 640 DDR3 should theoretically perform a lot faster than the GeForce GT 220 GDDR3 in general. (explain)

GeForce GT 640 DDR3		57024 MB/sec
GeForce GT 220 GDDR3		32384 MB/sec
	Difference: 24640 (76%)

Texel Rate

The GeForce GT 640 DDR3 is quite a bit (about 188%) faster with regards to texture filtering than the GeForce GT 220 GDDR3. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce GT 220 GDDR3		10000 Mtexels/sec
	Difference: 18800 (188%)

Pixel Rate

The GeForce GT 640 DDR3 should be a lot (approximately 188%) better at FSAA than the GeForce GT 220 GDDR3, and able to handle higher resolutions better. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce GT 220 GDDR3		5000 Mpixels/sec
	Difference: 9400 (188%)

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

Specifications

Memory Bandwidth: Bandwidth is the max amount of information (in units of megabytes per second) that can be moved past the external memory interface in one second. It's calculated by multiplying the interface width by the speed of its memory. If the card has DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied per second. This number is calculated by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines 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 lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.