Radeon HD 4850 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 works at a speed of 1125 MHz on this particular model. It features 640 SPUs along with 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 4850 1GB		110 Watts
	Difference: 30 Watts (38%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7770 should be a bit faster than the Radeon HD 4850 1GB overall. (explain)

Radeon HD 7770		72000 MB/sec
Radeon HD 4850 1GB		63552 MB/sec
	Difference: 8448 (13%)

Texel Rate

The Radeon HD 7770 will be quite a bit (more or less 60%) more effective at anisotropic filtering than the Radeon HD 4850 1GB. (explain)

Radeon HD 7770		40000 Mtexels/sec
Radeon HD 4850 1GB		25000 Mtexels/sec
	Difference: 15000 (60%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 7770 is the winner, by far. (explain)

Radeon HD 7770		16000 Mpixels/sec
Radeon HD 4850 1GB		10000 Mpixels/sec
	Difference: 6000 (60%)

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 moved over the external memory interface in one second. The number is worked out by multiplying the card's bus width by its memory speed. If it uses DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate 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 filling the screen with pixels (the image). The actual pixel rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.