Radeon HD 3870 512MB vs Radeon HD 4770

Intro

Compare those specs to the Radeon HD 4770, which makes use of a 40 nm design. AMD has set the core frequency at 750 MHz. The GDDR5 RAM works at a speed of 800 MHz on this particular card. It features 640(128x5) SPUs along with 32 Texture Address Units and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
Radeon HD 3870 512MB		106 Watts
	Difference: 26 Watts (33%)

Memory Bandwidth

The Radeon HD 3870 512MB, in theory, should perform a bit faster than the Radeon HD 4770 in general. (explain)

Radeon HD 3870 512MB		57600 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 6400 (13%)

Texel Rate

The Radeon HD 4770 is much (about 94%) better at anisotropic filtering than the Radeon HD 3870 512MB. (explain)

Radeon HD 4770		24000 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 11600 (94%)

Pixel Rate

The Radeon HD 3870 512MB is just a bit (more or less 3%) faster with regards to full screen anti-aliasing than the Radeon HD 4770, and will be capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon HD 3870 512MB		12400 Mpixels/sec
Radeon HD 4770		12000 Mpixels/sec
	Difference: 400 (3%)

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 (in units of megabytes per second) that can be moved past the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory clock speed. In the case of DDR memory, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed in one second. This number is worked out by multiplying the total number of texture units by the core clock speed of the chip. The better the texel rate, the better the video 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 graphics card can possibly record to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.