Radeon HD 4870 512MB vs Radeon HD 5770

Intro

Compare those specifications to the Radeon HD 5770, which has a GPU core clock speed of 850 MHz, and 1024 MB of GDDR5 RAM running at 1200 MHz through a 128-bit bus. It also features 800(160x5) SPUs, 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 4870 512MB		150 Watts
	Difference: 42 Watts (39%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4870 512MB should theoretically be much better than 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 is just a bit (about 13%) better at 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

If running with high levels of AA is important to you, then the Radeon HD 5770 is superior to the Radeon HD 4870 512MB, though not by far. (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: Bandwidth is the maximum amount of information (in units of megabytes per second) that can be transferred across the external memory interface in one second. The number is worked out by multiplying the bus width by its memory clock speed. In the case of DDR RAM, the result should be multiplied by 2 once 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, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs 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 lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.