GeForce 8800 GT 256MB vs GeForce GT 420

Intro

Compare those specifications to the GeForce GT 420, which comes with a GPU core clock speed of 700 MHz, and 2048 MB of GDDR3 RAM running at 900 MHz through a 128-bit bus. It also features 48 SPUs, 8 TAUs, and 4 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
GeForce 8800 GT 256MB		105 Watts
	Difference: 55 Watts (110%)

Memory Bandwidth

In theory, the GeForce 8800 GT 256MB should perform a lot faster than the GeForce GT 420 in general. (explain)

GeForce 8800 GT 256MB		44800 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 16000 (56%)

Texel Rate

The GeForce 8800 GT 256MB is a lot (approximately 500%) more effective at texture filtering than the GeForce GT 420. (explain)

GeForce 8800 GT 256MB		33600 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 28000 (500%)

Pixel Rate

The GeForce 8800 GT 256MB should be much (approximately 243%) faster with regards to anti-aliasing than the GeForce GT 420, and also capable of handling higher screen resolutions better. (explain)

GeForce 8800 GT 256MB		9600 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 6800 (243%)

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 maximum amount of data (counted in megabytes per second) that can be transferred past the external memory interface in a second. It's worked out by multiplying the card's bus width by its memory speed. In the case of DDR type RAM, the result should be multiplied by 2 once again. If it uses 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 can be processed per second. This figure is worked out by multiplying the total amount of texture units of the card by the core 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 per second.

Pixel Rate: Pixel rate is the maximum number of pixels that 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 Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.