Radeon HD 4870 512MB vs Radeon HD 6750

Intro

Compare that to the Radeon HD 6750, which features GPU clock speed of 725 MHz, and 512 MB of GDDR5 memory running at 1000 MHz through a 128-bit bus. It also is made up of 720 SPUs, 36 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 6750		86 Watts
Radeon HD 4870 512MB		150 Watts
	Difference: 64 Watts (74%)

Memory Bandwidth

The Radeon HD 4870 512MB should in theory be a lot faster than the Radeon HD 6750 overall. (explain)

Radeon HD 4870 512MB		115200 MB/sec
Radeon HD 6750		64000 MB/sec
	Difference: 51200 (80%)

Texel Rate

The Radeon HD 4870 512MB should be a bit (about 15%) faster with regards to AF than the Radeon HD 6750. (explain)

Radeon HD 4870 512MB		30000 Mtexels/sec
Radeon HD 6750		26100 Mtexels/sec
	Difference: 3900 (15%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 4870 512MB is superior to the Radeon HD 6750, but not by far. (explain)

Radeon HD 4870 512MB		12000 Mpixels/sec
Radeon HD 6750		11600 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 max amount of information (counted in megabytes per second) that can be transferred over the external memory interface in a second. It's calculated by multiplying the interface width by its memory clock speed. If the card has DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the 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 number of texture map elements (texels) that can be processed per second. This is worked out by multiplying the total texture units of the card by the core speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the card's 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, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.