Radeon HD 4830 512MB vs Radeon HD 4850 2GB

Intro

Compare all of that to the Radeon HD 4850 2GB, which features a core clock speed of 625 MHz and a GDDR4 memory speed of 993 MHz. It also makes use of a 256-bit memory bus, and uses a 55 nm design. It features 800(160x5) SPUs, 40 TAUs, and 16 ROPs.

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 speaking, the Radeon HD 4850 2GB should be a bit faster than the Radeon HD 4830 512MB overall. (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 is a lot (more or less 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

If using lots of anti-aliasing is important to you, then the Radeon HD 4850 2GB is superior to the Radeon HD 4830 512MB, but not by far. (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 largest amount of information (counted in MB per second) that can be moved past the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory speed. If it uses DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better 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 amount of texture map elements (texels) that are processed in one second. This figure is calculated 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 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 its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.