Radeon HD 4850 2GB vs Radeon HD 6750 1GB

Intro

Compare that to the Radeon HD 6750 1GB, which features a clock frequency of 725 MHz and a GDDR5 memory frequency of 1000 MHz. It also uses a 128-bit memory bus, and makes use of a 40 nm design. It is made up of 720 SPUs, 36 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6750 1GB		86 Watts
Radeon HD 4850 2GB		110 Watts
	Difference: 24 Watts (28%)

Memory Bandwidth

The Radeon HD 6750 1GB, in theory, should be a small bit faster than the Radeon HD 4850 2GB overall. (explain)

Radeon HD 6750 1GB		64000 MB/sec
Radeon HD 4850 2GB		63552 MB/sec
	Difference: 448 (1%)

Texel Rate

The Radeon HD 6750 1GB should be a bit (more or less 4%) more effective at anisotropic filtering than the Radeon HD 4850 2GB. (explain)

Radeon HD 6750 1GB		26100 Mtexels/sec
Radeon HD 4850 2GB		25000 Mtexels/sec
	Difference: 1100 (4%)

Pixel Rate

The Radeon HD 6750 1GB should be a bit (approximately 16%) better at anti-aliasing than the Radeon HD 4850 2GB, and also capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon HD 6750 1GB		11600 Mpixels/sec
Radeon HD 4850 2GB		10000 Mpixels/sec
	Difference: 1600 (16%)

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 largest amount of information (in units of MB per second) that can be transferred past the external memory interface within a second. It's calculated by multiplying the card's interface width by its memory speed. In the case of DDR type memory, 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 texture map elements (texels) that can be applied per second. This is worked out by multiplying the total texture units of the card by the core 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 in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly record to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.