Radeon HD 4750 vs Radeon HD 7850

Intro

Compare those specs to the Radeon HD 7850, which has GPU core speed of 860 MHz, and 2048 MB of GDDR5 memory set to run at 1200 MHz through a 256-bit bus. It also is made up of 1024 SPUs, 64 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4750		75 Watts
Radeon HD 7850		130 Watts
	Difference: 55 Watts (73%)

Memory Bandwidth

As far as performance goes, the Radeon HD 7850 should theoretically be a lot better than the Radeon HD 4750 overall. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 4750		51200 MB/sec
	Difference: 102400 (200%)

Texel Rate

The Radeon HD 7850 should be a lot (more or less 136%) more effective at texture filtering than the Radeon HD 4750. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 4750		23360 Mtexels/sec
	Difference: 31680 (136%)

Pixel Rate

The Radeon HD 7850 is much (approximately 136%) faster with regards to FSAA than the Radeon HD 4750, and capable of handling higher resolutions more effectively. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 4750		11680 Mpixels/sec
	Difference: 15840 (136%)

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 (in units of MB per second) that can be moved over the external memory interface in a second. It is worked out by multiplying the bus width by its memory speed. If it uses DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This is worked out by multiplying the total texture units by the core speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly write to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.