Radeon HD 4890 1GB vs Radeon HD 6750

Intro

Compare those specifications to the Radeon HD 6750, which has a GPU core 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 Stream Processors, 36 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6750		86 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 104 Watts (121%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4890 1GB should be quite a bit faster than the Radeon HD 6750 overall. (explain)

Radeon HD 4890 1GB		124800 MB/sec
Radeon HD 6750		64000 MB/sec
	Difference: 60800 (95%)

Texel Rate

The Radeon HD 4890 1GB is a lot (more or less 53%) better at anisotropic filtering than the Radeon HD 6750. (explain)

Radeon HD 4890 1GB		40000 Mtexels/sec
Radeon HD 6750		26100 Mtexels/sec
	Difference: 13900 (53%)

Pixel Rate

The Radeon HD 4890 1GB should be a lot (about 38%) better at full screen anti-aliasing than the Radeon HD 6750, and capable of handling higher screen resolutions without slowing down too much. (explain)

Radeon HD 4890 1GB		16000 Mpixels/sec
Radeon HD 6750		11600 Mpixels/sec
	Difference: 4400 (38%)

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 max amount of data (measured in megabytes per second) that can be moved past the external memory interface in one second. The number is worked out by multiplying the bus width by the speed of its memory. In the case of DDR type memory, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, 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 texture map elements (texels) that are processed per second. This figure is calculated 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 its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.