Radeon HD 6770 1GB vs Radeon HD 7990

Intro

Compare all that to the Radeon HD 7990, which has clock speeds of 950 MHz on the GPU, and 1500 MHz on the 3072 MB of GDDR5 RAM. It features 2048 SPUs as well as 128 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6770 1GB		108 Watts
Radeon HD 7990		375 Watts
	Difference: 267 Watts (247%)

Memory Bandwidth

The Radeon HD 7990 should in theory perform quite a bit faster than the Radeon HD 6770 1GB in general. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 6770 1GB		67200 MB/sec
	Difference: 508800 (757%)

Texel Rate

The Radeon HD 7990 is much (about 576%) better at texture filtering than the Radeon HD 6770 1GB. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 6770 1GB		36000 Mtexels/sec
	Difference: 207200 (576%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 7990 is superior to the Radeon HD 6770 1GB, and very much so. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 6770 1GB		14400 Mpixels/sec
	Difference: 46400 (322%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the largest amount of data (measured in MB per second) that can be moved across the external memory interface in a second. The number is calculated by multiplying the interface width by its memory clock speed. If it uses DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This number is calculated by multiplying the total texture units of the card by the core speed of the chip. The higher the texel rate, the better the graphics 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 maximum number of pixels that the graphics chip could possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.