GeForce 8600 GT 1GB GDDR3 vs GeForce GT 420

Intro

Compare that to the GeForce GT 420, which features clock speeds of 700 MHz on the GPU, and 900 MHz on the 2048 MB of GDDR3 memory. 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 8600 GT 1GB GDDR3		47 Watts
GeForce GT 420		50 Watts
	Difference: 3 Watts (6%)

Memory Bandwidth

Performance-wise, the GeForce GT 420 should in theory be quite a bit superior to the GeForce 8600 GT 1GB GDDR3 in general. (explain)

GeForce GT 420		28800 MB/sec
GeForce 8600 GT 1GB GDDR3		22400 MB/sec
	Difference: 6400 (29%)

Texel Rate

The GeForce 8600 GT 1GB GDDR3 should be much (more or less 54%) more effective at texture filtering than the GeForce GT 420. (explain)

GeForce 8600 GT 1GB GDDR3		8640 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 3040 (54%)

Pixel Rate

The GeForce 8600 GT 1GB GDDR3 will be much (more or less 54%) faster with regards to AA than the GeForce GT 420, and also will be capable of handling higher screen resolutions better. (explain)

GeForce 8600 GT 1GB GDDR3		4320 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 1520 (54%)

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 information (in units of MB per second) that can be moved across the external memory interface in one second. It is calculated by multiplying the bus width by the speed of its memory. If it uses DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed in one second. This figure is calculated by multiplying the total 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 processed in one second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly record to its 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 core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.