GeForce GT 220 GDDR3 vs GeForce GT 640 DDR3

Intro

Compare those specifications to the GeForce GT 640 DDR3, which uses a 28 nm design. nVidia has clocked the core frequency at 900 MHz. The DDR3 RAM is set to run at a speed of 1782 MHz on this particular model. It features 384 SPUs along with 32 Texture Address Units and 16 ROPs.

Display Graphs

Hide Graphs

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 in theory be a lot faster than the GeForce GT 220 GDDR3 overall. (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 will be a lot (approximately 188%) more effective at AF 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 quite a bit (about 188%) better at AA than the GeForce GT 220 GDDR3, and should be able to handle higher resolutions without losing too much performance. (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 largest amount of information (in units of MB per second) that can be moved past the external memory interface in a second. It is calculated by multiplying the card's interface width by the speed of its memory. In the case of DDR memory, it must be multiplied by 2 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 anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed 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 card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could 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 clock 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 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 get to the max fill rate.