Radeon HD 4850 X2 1GB vs Radeon HD 5770

Intro

Compare all that to the Radeon HD 5770, which comes with a core clock speed of 850 MHz and a GDDR5 memory frequency of 1200 MHz. It also uses a 128-bit bus, and makes use of a 40 nm design. It is made up of 800(160x5) SPUs, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 5770		108 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 142 Watts (131%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4850 X2 1GB should perform quite a bit faster than the Radeon HD 5770 in general. (explain)

Radeon HD 4850 X2 1GB		127104 MB/sec
Radeon HD 5770		76800 MB/sec
	Difference: 50304 (66%)

Texel Rate

The Radeon HD 4850 X2 1GB is quite a bit (approximately 47%) faster with regards to texture filtering than the Radeon HD 5770. (explain)

Radeon HD 4850 X2 1GB		50000 Mtexels/sec
Radeon HD 5770		34000 Mtexels/sec
	Difference: 16000 (47%)

Pixel Rate

The Radeon HD 4850 X2 1GB will be a lot (approximately 47%) better at full screen anti-aliasing than the Radeon HD 5770, and should be able to handle higher resolutions while still performing well. (explain)

Radeon HD 4850 X2 1GB		20000 Mpixels/sec
Radeon HD 5770		13600 Mpixels/sec
	Difference: 6400 (47%)

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: Bandwidth is the max amount of data (measured in megabytes per second) that can be transferred over the external memory interface in one second. It's calculated by multiplying the interface width by its memory clock speed. If the card has DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster 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 amount of texture map elements (texels) that can be applied in one second. This is worked out by multiplying the total number of texture units by the core clock speed of the chip. The better the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

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