GeForce 8600 GT 512MB GDDR3 vs GeForce GT 420

Intro

Compare all that to the GeForce GT 420, which uses a 40 nm design. nVidia has clocked the core speed at 700 MHz. The GDDR3 RAM is set to run at a frequency of 900 MHz on this model. It features 48 SPUs as well as 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 512MB GDDR3		47 Watts
GeForce GT 420		50 Watts
	Difference: 3 Watts (6%)

Memory Bandwidth

The GeForce GT 420 should in theory be a lot faster than the GeForce 8600 GT 512MB GDDR3 in general. (explain)

GeForce GT 420		28800 MB/sec
GeForce 8600 GT 512MB GDDR3		22400 MB/sec
	Difference: 6400 (29%)

Texel Rate

The GeForce 8600 GT 512MB GDDR3 should be quite a bit (about 54%) faster with regards to texture filtering than the GeForce GT 420. (explain)

GeForce 8600 GT 512MB GDDR3		8640 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 3040 (54%)

Pixel Rate

If using a high screen resolution is important to you, then the GeForce 8600 GT 512MB GDDR3 is a better choice, by a large margin. (explain)

GeForce 8600 GT 512MB 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 max amount of information (counted in MB per second) that can be transferred past the external memory interface in one second. The number is worked out by multiplying the card's bus width by the speed of its memory. If the card has DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This is worked out by multiplying the total amount of texture units by the core speed of the chip. The better 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 a second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly write to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the clock 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 lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.