GeForce 8600 GT 512MB GDDR3 vs GeForce GT 420

Intro

Compare those specs 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 RAM. It features 48 SPUs along with 8 TAUs 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

Theoretically speaking, the GeForce GT 420 is 29% quicker than the GeForce 8600 GT 512MB GDDR3 in general, because of its higher data rate. (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 will be much (more or less 54%) faster with regards to anisotropic 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

The GeForce 8600 GT 512MB GDDR3 is a lot (more or less 54%) more effective at FSAA than the GeForce GT 420, and capable of handling higher screen resolutions while still performing well. (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: Memory bandwidth is the maximum amount of data (counted in MB per second) that can be transferred past the external memory interface in one second. It is calculated by multiplying the bus width by its memory clock speed. If it uses DDR type RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This is worked out by multiplying the total texture units of the card by the core speed of the chip. The higher the texel rate, 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 maximum number of pixels the video card can 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 clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.