GeForce GT 420 vs Radeon HD 3850 256MB

Intro

Compare those specs to the Radeon HD 3850 256MB, which features core speeds of 668 MHz on the GPU, and 828 MHz on the 256 MB of GDDR3 RAM. It features 320(64x5) SPUs as well as 16 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
Radeon HD 3850 256MB		75 Watts
	Difference: 25 Watts (50%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 3850 256MB is 84% faster than the GeForce GT 420 overall, due to its greater data rate. (explain)

Radeon HD 3850 256MB		52992 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 24192 (84%)

Texel Rate

The Radeon HD 3850 256MB will be a lot (approximately 91%) better at anisotropic filtering than the GeForce GT 420. (explain)

Radeon HD 3850 256MB		10688 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 5088 (91%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 3850 256MB is a better choice, by a large margin. (explain)

Radeon HD 3850 256MB		10688 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 7888 (282%)

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 largest amount of data (measured in megabytes per second) that can be transferred over the external memory interface within a second. It is worked out by multiplying the interface width by the speed of its memory. If the card has DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka 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 maximum fill rate.