Radeon HD 4790 vs Radeon HD 6770

Intro

Compare all that to the Radeon HD 6770, which has a core clock frequency of 900 MHz and a GDDR5 memory frequency of 1050 MHz. It also makes use of a 128-bit memory bus, and makes use of a 40 nm design. It is made up of 800 SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 4790 should be 52% faster than the Radeon HD 6770 overall, due to its higher data rate. (explain)

Radeon HD 4790		102400 MB/sec
Radeon HD 6770		67200 MB/sec
	Difference: 35200 (52%)

Texel Rate

The Radeon HD 6770 is a lot (more or less 88%) faster with regards to anisotropic filtering than the Radeon HD 4790. (explain)

Radeon HD 6770		36000 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 16800 (88%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 6770 is a better choice, and very much so. (explain)

Radeon HD 6770		14400 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 4800 (50%)

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 (in units of MB per second) that can be moved over the external memory interface in one second. It's calculated by multiplying the interface width by its memory clock speed. In the case of DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly record to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.