Radeon HD 3870 512MB vs Radeon HD 4750

Intro

Compare those specs to the Radeon HD 4750, which features a core clock frequency of 730 MHz and a GDDR5 memory frequency of 800 MHz. It also features a 128-bit memory bus, and makes use of a 40 nm design. It is comprised of 640(128x5) SPUs, 32 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4750		75 Watts
Radeon HD 3870 512MB		106 Watts
	Difference: 31 Watts (41%)

Memory Bandwidth

Performance-wise, the Radeon HD 3870 512MB should theoretically be a small bit superior to the Radeon HD 4750 overall. (explain)

Radeon HD 3870 512MB		57600 MB/sec
Radeon HD 4750		51200 MB/sec
	Difference: 6400 (13%)

Texel Rate

The Radeon HD 4750 is much (about 88%) more effective at AF than the Radeon HD 3870 512MB. (explain)

Radeon HD 4750		23360 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 10960 (88%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 3870 512MB is the winner, though only just barely. (explain)

Radeon HD 3870 512MB		12400 Mpixels/sec
Radeon HD 4750		11680 Mpixels/sec
	Difference: 720 (6%)

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 data (counted in MB per second) that can be transferred past the external memory interface in one second. It's calculated by multiplying the interface width by its memory speed. If it uses DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied per second. This number is calculated by multiplying the total number of texture units by the core clock speed of the chip. The higher this number, the better the graphics 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 maximum amount of pixels that the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.