Radeon HD 4750 vs Radeon HD 4830 512MB

Intro

Compare those specs to the Radeon HD 4830 512MB, which has a clock frequency of 575 MHz and a GDDR3 memory frequency of 900 MHz. It also makes use of a 256-bit bus, and uses a 55 nm design. It features 640(128x5) SPUs, 32 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 4750		75 Watts
Radeon HD 4830 512MB		95 Watts
	Difference: 20 Watts (27%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4830 512MB should perform a little bit faster than the Radeon HD 4750 in general. (explain)

Radeon HD 4830 512MB		57600 MB/sec
Radeon HD 4750		51200 MB/sec
	Difference: 6400 (13%)

Texel Rate

The Radeon HD 4750 is much (approximately 27%) more effective at texture filtering than the Radeon HD 4830 512MB. (explain)

Radeon HD 4750		23360 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 4960 (27%)

Pixel Rate

The Radeon HD 4750 will be a lot (about 27%) faster with regards to full screen anti-aliasing than the Radeon HD 4830 512MB, and also should be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 4750		11680 Mpixels/sec
Radeon HD 4830 512MB		9200 Mpixels/sec
	Difference: 2480 (27%)

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 data (in units of MB per second) that can be transported past the external memory interface in a second. It's worked out by multiplying the card's interface width by the speed of its memory. In the case of DDR type memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics 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 Render Output Units by the clock 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 also depends on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.