Radeon HD 4850 1GB vs Radeon HD 6770

Intro

Compare all that to the Radeon HD 6770, which has clock speeds of 900 MHz on the GPU, and 1050 MHz on the 512 MB of GDDR5 memory. It features 800 SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6770		108 Watts
Radeon HD 4850 1GB		110 Watts
	Difference: 2 Watts (2%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 6770 should be 6% quicker than the Radeon HD 4850 1GB overall, due to its greater data rate. (explain)

Radeon HD 6770		67200 MB/sec
Radeon HD 4850 1GB		63552 MB/sec
	Difference: 3648 (6%)

Texel Rate

The Radeon HD 6770 should be much (about 44%) faster with regards to AF than the Radeon HD 4850 1GB. (explain)

Radeon HD 6770		36000 Mtexels/sec
Radeon HD 4850 1GB		25000 Mtexels/sec
	Difference: 11000 (44%)

Pixel Rate

The Radeon HD 6770 will be a lot (more or less 44%) faster with regards to FSAA than the Radeon HD 4850 1GB, and also will be capable of handling higher resolutions without slowing down too much. (explain)

Radeon HD 6770		14400 Mpixels/sec
Radeon HD 4850 1GB		10000 Mpixels/sec
	Difference: 4400 (44%)

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 transported over the external memory interface in one second. It's worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better 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 texture map elements (texels) that can be applied per second. This figure is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.