Radeon HD 4830 512MB vs Radeon HD 4850 1GB

Intro

Compare all of that to the Radeon HD 4850 1GB, which has a core clock frequency of 625 MHz and a GDDR4 memory frequency of 993 MHz. It also uses a 256-bit memory bus, and uses a 55 nm design. It 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 1GB		110 Watts
	Difference: 15 Watts (16%)

Memory Bandwidth

Performance-wise, the Radeon HD 4850 1GB should theoretically be just a bit better than the Radeon HD 4830 512MB in general. (explain)

Radeon HD 4850 1GB		63552 MB/sec
Radeon HD 4830 512MB		57600 MB/sec
	Difference: 5952 (10%)

Texel Rate

The Radeon HD 4850 1GB is a lot (more or less 36%) faster with regards to texture filtering than the Radeon HD 4830 512MB. (explain)

Radeon HD 4850 1GB		25000 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 6600 (36%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 4850 1GB is the winner, but it probably won't make a huge difference. (explain)

Radeon HD 4850 1GB		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: Bandwidth is the max amount of information (in units of MB per second) that can be moved past the external memory interface within a second. The number is calculated by multiplying the card's bus width by its memory speed. In the case of DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the better 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 can be applied in one second. This number 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 card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the clock speed of the card. 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 - the lower the bandwidth is, the lower the ability to get to the max fill rate.