Radeon HD 4870 512MB vs Radeon HD 5770

Intro

Compare all that to the Radeon HD 5770, which features GPU clock speed of 850 MHz, and 1024 MB of GDDR5 memory running at 1200 MHz through a 128-bit bus. It also is made up of 800(160x5) Stream Processors, 40 Texture Address Units, and 16 Raster Operation Units.

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

Performance-wise, the Radeon HD 4870 512MB should in theory be a lot superior to the Radeon HD 5770 in general. (explain)

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

Texel Rate

The Radeon HD 5770 will be just a bit (more or less 13%) faster with regards to texture 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 (more or less 13%) faster with regards to FSAA than the Radeon HD 4870 512MB, and should be capable of handling 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 max amount of data (measured in MB per second) that can be transported over the external memory interface in one second. It is worked out by multiplying the interface width by its memory clock speed. If the card has DDR type memory, it must 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, HDR 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 worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.