Radeon HD 4850 512MB vs Radeon HD 7850

Intro

Compare that to the Radeon HD 7850, which comes with a core clock frequency of 860 MHz and a GDDR5 memory speed of 1200 MHz. It also makes use of a 256-bit memory bus, and makes use of a 28 nm design. It features 1024 SPUs, 64 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 512MB		110 Watts
Radeon HD 7850		130 Watts
	Difference: 20 Watts (18%)

Memory Bandwidth

In theory, the Radeon HD 7850 will be 142% quicker than the Radeon HD 4850 512MB in general, due to its higher bandwidth. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 4850 512MB		63552 MB/sec
	Difference: 90048 (142%)

Texel Rate

The Radeon HD 7850 should be quite a bit (approximately 120%) more effective at texture filtering than the Radeon HD 4850 512MB. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 4850 512MB		25000 Mtexels/sec
	Difference: 30040 (120%)

Pixel Rate

The Radeon HD 7850 is much (about 175%) more effective at AA than the Radeon HD 4850 512MB, and also will be able to handle higher resolutions without losing too much performance. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 4850 512MB		10000 Mpixels/sec
	Difference: 17520 (175%)

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 maximum amount of data (measured in megabytes per second) that can be moved past the external memory interface in one second. It is worked out by multiplying the interface width by its memory clock speed. If the card has DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed in one second. This is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the graphics 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 that the graphics card can possibly write to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs 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 lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.