GeForce GT 420 vs Radeon HD 4830 1GB

Intro

Compare all of that to the Radeon HD 4830 1GB, which features a core clock frequency of 575 MHz and a GDDR4 memory frequency of 900 MHz. It also makes use of a 256-bit memory bus, and makes use of a 55 nm design. It is comprised of 640(128x5) SPUs, 32 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
Radeon HD 4830 1GB		95 Watts
	Difference: 45 Watts (90%)

Memory Bandwidth

In theory, the Radeon HD 4830 1GB should be much faster than the GeForce GT 420 in general. (explain)

Radeon HD 4830 1GB		57600 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 28800 (100%)

Texel Rate

The Radeon HD 4830 1GB should be much (approximately 229%) more effective at anisotropic filtering than the GeForce GT 420. (explain)

Radeon HD 4830 1GB		18400 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 12800 (229%)

Pixel Rate

The Radeon HD 4830 1GB will be a lot (more or less 229%) better at AA than the GeForce GT 420, and able to handle higher resolutions more effectively. (explain)

Radeon HD 4830 1GB		9200 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 6400 (229%)

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 information (in units of megabytes per second) that can be transferred across the external memory interface in a second. It's worked out by multiplying the bus width by its memory speed. If it uses DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the 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 number of texture map elements (texels) that are processed in one second. This is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the 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 maximum number of pixels the video card can possibly write to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the clock speed of the card. 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 quite a few 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.