Radeon HD 4830 1GB vs Radeon HD 7770

Intro

Compare all of that to the Radeon HD 7770, which has a clock speed of 1000 MHz and a GDDR5 memory frequency of 1125 MHz. It also features a 128-bit bus, and uses a 28 nm design. It features 640 SPUs, 40 TAUs, and 16 Raster Operation 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

The Radeon HD 7770, in theory, should perform much faster than the Radeon HD 4830 1GB in general. (explain)

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

Texel Rate

The Radeon HD 7770 should be much (about 117%) better 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

The Radeon HD 7770 will be quite a bit (approximately 74%) better at full screen anti-aliasing than the Radeon HD 4830 1GB, and able to handle higher screen resolutions while still performing well. (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 maximum amount of data (in units of megabytes per second) that can be moved across the external memory interface in one second. It's calculated by multiplying the card's interface width by the speed of its memory. If it uses DDR memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This figure is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the video card will be at handling 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 could possibly write to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.