Radeon HD 4870 1GB vs Radeon HD 5770

Intro

Compare all of that to the Radeon HD 5770, which features GPU clock speed of 850 MHz, and 1024 MB of GDDR5 RAM set to run at 1200 MHz through a 128-bit bus. It also is comprised of 800(160x5) SPUs, 40 TAUs, 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 1GB		150 Watts
	Difference: 42 Watts (39%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4870 1GB will be 50% faster than the Radeon HD 5770 in general, because of its higher data rate. (explain)

Radeon HD 4870 1GB		115200 MB/sec
Radeon HD 5770		76800 MB/sec
	Difference: 38400 (50%)

Texel Rate

The Radeon HD 5770 should be a small bit (about 13%) better at anisotropic filtering than the Radeon HD 4870 1GB. (explain)

Radeon HD 5770		34000 Mtexels/sec
Radeon HD 4870 1GB		30000 Mtexels/sec
	Difference: 4000 (13%)

Pixel Rate

The Radeon HD 5770 should be a bit (approximately 13%) better at AA than the Radeon HD 4870 1GB, and should be able to handle higher screen resolutions without losing too much performance. (explain)

Radeon HD 5770		13600 Mpixels/sec
Radeon HD 4870 1GB		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 across the external memory interface within a second. It is worked out by multiplying the card's bus width by the speed of its memory. In the case of DDR type RAM, it should be multiplied by 2 once 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, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This figure is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the graphics 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 the graphics card can possibly record to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of ROPs by the the core 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 also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.