Radeon HD 4870 512MB vs Radeon HD 5770

Intro

Compare all of that to the Radeon HD 5770, which uses a 40 nm design. AMD has set the core frequency at 850 MHz. The GDDR5 RAM is set to run at a speed of 1200 MHz on this specific model. It features 800(160x5) SPUs as well as 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 4870 512MB		150 Watts
	Difference: 42 Watts (39%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4870 512MB should theoretically be quite a bit superior to the Radeon HD 5770 overall. (explain)

Radeon HD 4870 512MB		115200 MB/sec
Radeon HD 5770		76800 MB/sec
	Difference: 38400 (50%)

Texel Rate

The Radeon HD 5770 should be a bit (about 13%) faster with regards to anisotropic filtering than the Radeon HD 4870 512MB. (explain)

Radeon HD 5770		34000 Mtexels/sec
Radeon HD 4870 512MB		30000 Mtexels/sec
	Difference: 4000 (13%)

Pixel Rate

The Radeon HD 5770 is a bit (approximately 13%) more effective at anti-aliasing than the Radeon HD 4870 512MB, and will be able to handle higher screen resolutions while still performing well. (explain)

Radeon HD 5770		13600 Mpixels/sec
Radeon HD 4870 512MB		12000 Mpixels/sec
	Difference: 1600 (13%)

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 largest amount of information (measured in MB per second) that can be moved over the external memory interface within a second. It is calculated by multiplying the interface width by its memory clock speed. In the case of DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly write to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.