GeForce 8600 GT 1GB GDDR3 vs GeForce GT 420

Intro

Compare those specifications to the GeForce GT 420, which comes with core 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 TAUs and 4 ROPs.

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

Theoretically speaking, the GeForce GT 420 will be 29% faster than the GeForce 8600 GT 1GB GDDR3 in general, due to its greater data rate. (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 will be a lot (approximately 54%) better 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

If running with lots of anti-aliasing is important to you, then the GeForce 8600 GT 1GB GDDR3 is the winner, and very much so. (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 (counted in MB per second) that can be moved over the external memory interface in one second. It is worked out by multiplying the interface width by its memory clock speed. In the case of DDR type memory, it should be multiplied by 2 again. If 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 high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed per second. This is worked out by multiplying the total texture units by the core clock speed of the chip. The higher this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant 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 reach the maximum fill rate.