Radeon HD 4830 1GB vs Radeon HD 7770

Intro

Compare those specs to the Radeon HD 7770, which uses a 28 nm design. AMD has clocked the core frequency at 1000 MHz. The GDDR5 memory is set to run at a frequency of 1125 MHz on this model. It features 640 SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7770		80 Watts
Radeon HD 4830 1GB		95 Watts
	Difference: 15 Watts (19%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7770 is 25% faster than the Radeon HD 4830 1GB overall, because of its higher data rate. (explain)

Radeon HD 7770		72000 MB/sec
Radeon HD 4830 1GB		57600 MB/sec
	Difference: 14400 (25%)

Texel Rate

The Radeon HD 7770 is a lot (approximately 117%) more effective at AF than the Radeon HD 4830 1GB. (explain)

Radeon HD 7770		40000 Mtexels/sec
Radeon HD 4830 1GB		18400 Mtexels/sec
	Difference: 21600 (117%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 7770 is the winner, by a large margin. (explain)

Radeon HD 7770		16000 Mpixels/sec
Radeon HD 4830 1GB		9200 Mpixels/sec
	Difference: 6800 (74%)

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 (counted in megabytes per second) that can be transported past the external memory interface in a second. It's worked out by multiplying the bus width by its memory speed. If the card has DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This figure is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher this number, the better the video 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 most pixels the video card could possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units 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 rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.