GeForce GT 220 GDDR3 vs GeForce GT 420

Intro

Compare all of that to the GeForce GT 420, which uses a 40 nm design. nVidia has clocked the core speed at 700 MHz. The GDDR3 RAM runs at a frequency of 900 MHz on this particular model. It features 48 SPUs along with 8 Texture Address Units and 4 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
GeForce GT 220 GDDR3		58 Watts
	Difference: 8 Watts (16%)

Memory Bandwidth

Performance-wise, the GeForce GT 220 GDDR3 should theoretically be a small bit better than the GeForce GT 420 in general. (explain)

GeForce GT 220 GDDR3		32384 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 3584 (12%)

Texel Rate

The GeForce GT 220 GDDR3 will be a lot (approximately 79%) more effective at anisotropic filtering than the GeForce GT 420. (explain)

GeForce GT 220 GDDR3		10000 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 4400 (79%)

Pixel Rate

The GeForce GT 220 GDDR3 is quite a bit (approximately 79%) better at full screen anti-aliasing than the GeForce GT 420, and should be capable of handling higher screen resolutions better. (explain)

GeForce GT 220 GDDR3		5000 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 2200 (79%)

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 data (counted in MB per second) that can be moved past the external memory interface in a second. The number is worked out by multiplying the card's interface width by the speed of its memory. If the card has DDR RAM, the result should 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 anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This number is worked out by multiplying the total texture units by the core clock speed of the chip. The higher the texel rate, the better the 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 most pixels the graphics card can possibly record to the local memory in one 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 - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.