GeForce 8600 GT 1GB GDDR3 vs GeForce GT 420

Intro

Compare all that to the GeForce GT 420, which uses a 40 nm design. nVidia has set the core frequency at 700 MHz. The GDDR3 RAM runs at a speed of 900 MHz on this specific model. It features 48 SPUs as well as 8 Texture Address Units 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

The GeForce GT 420, in theory, should be much faster than the GeForce 8600 GT 1GB GDDR3 overall. (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 much (about 54%) faster with regards to 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 superior to the GeForce GT 420, by far. (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: Memory bandwidth is the maximum amount of information (counted in MB per second) that can be transported across the external memory interface within a second. It is calculated by multiplying the interface width by its memory clock speed. If it uses DDR memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the 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 amount of texture map elements (texels) that can be processed per second. This number is worked out by multiplying the total number of 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 applied per second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs by the the core clock speed. 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 of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.