Radeon HD 4850 512MB vs Radeon HD 5770

Intro

Compare those specifications to the Radeon HD 5770, which makes use of a 40 nm design. AMD has clocked the core speed at 850 MHz. The GDDR5 memory is set to run at a speed of 1200 MHz on this specific card. It features 800(160x5) SPUs along with 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 512MB		110 Watts
	Difference: 2 Watts (2%)

Memory Bandwidth

In theory, the Radeon HD 5770 is 21% quicker than the Radeon HD 4850 512MB overall, because of its greater bandwidth. (explain)

Radeon HD 5770		76800 MB/sec
Radeon HD 4850 512MB		63552 MB/sec
	Difference: 13248 (21%)

Texel Rate

The Radeon HD 5770 should be much (approximately 36%) faster with regards to AF than the Radeon HD 4850 512MB. (explain)

Radeon HD 5770		34000 Mtexels/sec
Radeon HD 4850 512MB		25000 Mtexels/sec
	Difference: 9000 (36%)

Pixel Rate

The Radeon HD 5770 should be much (approximately 36%) better at AA than the Radeon HD 4850 512MB, and also should be able to handle higher resolutions while still performing well. (explain)

Radeon HD 5770		13600 Mpixels/sec
Radeon HD 4850 512MB		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: Memory bandwidth is the maximum amount of data (measured in megabytes per second) that can be transferred across the external memory interface within a second. The number is worked out by multiplying the card's interface width by the speed of its memory. If it uses DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This figure is worked out by multiplying the total 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 applied in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write to the local memory in one 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 - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel 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 ability to reach the maximum fill rate.