Radeon HD 4770 vs Radeon HD 4830 1GB

Intro

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

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
Radeon HD 4830 1GB		95 Watts
	Difference: 15 Watts (19%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4830 1GB should in theory be a bit superior to the Radeon HD 4770 overall. (explain)

Radeon HD 4830 1GB		57600 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 6400 (13%)

Texel Rate

The Radeon HD 4770 is a lot (about 30%) more effective at anisotropic filtering than the Radeon HD 4830 1GB. (explain)

Radeon HD 4770		24000 Mtexels/sec
Radeon HD 4830 1GB		18400 Mtexels/sec
	Difference: 5600 (30%)

Pixel Rate

The Radeon HD 4770 will be much (approximately 30%) faster with regards to full screen anti-aliasing than the Radeon HD 4830 1GB, and will be able to handle higher resolutions without slowing down too much. (explain)

Radeon HD 4770		12000 Mpixels/sec
Radeon HD 4830 1GB		9200 Mpixels/sec
	Difference: 2800 (30%)

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 moved past the external memory interface in one second. The number is worked out by multiplying the card's bus width by its memory speed. In the case of DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total texture units by the core 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 in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly record to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel 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 reach the max fill rate.