Radeon HD 4850 2GB vs Radeon HD 5770

Intro

Compare those specs to the Radeon HD 5770, which features clock speeds of 850 MHz on the GPU, and 1200 MHz on the 1024 MB of GDDR5 RAM. It features 800(160x5) 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 5770		108 Watts
Radeon HD 4850 2GB		110 Watts
	Difference: 2 Watts (2%)

Memory Bandwidth

In theory, the Radeon HD 5770 should be 21% faster than the Radeon HD 4850 2GB overall, because of its higher bandwidth. (explain)

Radeon HD 5770		76800 MB/sec
Radeon HD 4850 2GB		63552 MB/sec
	Difference: 13248 (21%)

Texel Rate

The Radeon HD 5770 should be quite a bit (approximately 36%) more effective at AF than the Radeon HD 4850 2GB. (explain)

Radeon HD 5770		34000 Mtexels/sec
Radeon HD 4850 2GB		25000 Mtexels/sec
	Difference: 9000 (36%)

Pixel Rate

The Radeon HD 5770 is quite a bit (about 36%) better at full screen anti-aliasing than the Radeon HD 4850 2GB, and should be capable of handling higher resolutions while still performing well. (explain)

Radeon HD 5770		13600 Mpixels/sec
Radeon HD 4850 2GB		10000 Mpixels/sec
	Difference: 3600 (36%)

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: Bandwidth is the max amount of information (measured in megabytes per second) that can be transferred over the external memory interface in one second. It's calculated by multiplying the bus width by the speed of its memory. In the case of DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the bandwidth is, 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 number of texture map elements (texels) that can be applied per second. This figure is worked out 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 video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Raster Operations Pipelines by the clock speed of the card. 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 is also dependant on quite a few 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.