Radeon HD 4830 512MB vs Radeon HD 4850 2GB

Intro

Compare those specs to the Radeon HD 4850 2GB, which has a GPU core clock speed of 625 MHz, and 2048 MB of GDDR4 memory set to run at 993 MHz through a 256-bit bus. It also is made up of 800(160x5) SPUs, 40 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 512MB		95 Watts
Radeon HD 4850 2GB		110 Watts
	Difference: 15 Watts (16%)

Memory Bandwidth

Theoretically, the Radeon HD 4850 2GB should be a small bit faster than the Radeon HD 4830 512MB in general. (explain)

Radeon HD 4850 2GB		63552 MB/sec
Radeon HD 4830 512MB		57600 MB/sec
	Difference: 5952 (10%)

Texel Rate

The Radeon HD 4850 2GB will be much (approximately 36%) better at texture filtering than the Radeon HD 4830 512MB. (explain)

Radeon HD 4850 2GB		25000 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 6600 (36%)

Pixel Rate

The Radeon HD 4850 2GB is just a bit (more or less 9%) faster with regards to full screen anti-aliasing than the Radeon HD 4830 512MB, and also will be able to handle higher screen resolutions while still performing well. (explain)

Radeon HD 4850 2GB		10000 Mpixels/sec
Radeon HD 4830 512MB		9200 Mpixels/sec
	Difference: 800 (9%)

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 max amount of information (in units of megabytes per second) that can be transferred over the external memory interface in one second. It is worked out by multiplying the bus width by its memory clock speed. If the card has DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly record to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.