Radeon HD 5870 vs Radeon HD 7770

Intro

Compare all of that to the Radeon HD 7770, which makes use of a 28 nm design. AMD has set the core speed at 1000 MHz. The GDDR5 memory works at a speed of 1125 MHz on this particular model. It features 640 SPUs as well as 40 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7770		80 Watts
Radeon HD 5870		188 Watts
	Difference: 108 Watts (135%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 5870 is 113% quicker than the Radeon HD 7770 overall, due to its greater data rate. (explain)

Radeon HD 5870		153600 MB/sec
Radeon HD 7770		72000 MB/sec
	Difference: 81600 (113%)

Texel Rate

The Radeon HD 5870 will be a lot (about 70%) more effective at AF than the Radeon HD 7770. (explain)

Radeon HD 5870		68000 Mtexels/sec
Radeon HD 7770		40000 Mtexels/sec
	Difference: 28000 (70%)

Pixel Rate

The Radeon HD 5870 should be quite a bit (about 70%) better at AA than the Radeon HD 7770, and also will be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 5870		27200 Mpixels/sec
Radeon HD 7770		16000 Mpixels/sec
	Difference: 11200 (70%)

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 (measured in MB per second) that can be transferred past the external memory interface within a second. It is calculated by multiplying the bus width by its memory clock speed. If it uses DDR type RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed per second. This number is worked out by multiplying the total amount of texture units of the card by the core 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 per second.

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.