Radeon HD 3850 512MB vs Radeon HD 4850 1GB

Intro

Compare all of that to the Radeon HD 4850 1GB, which comes with a clock frequency of 625 MHz and a GDDR4 memory speed of 993 MHz. It also uses a 256-bit bus, and uses a 55 nm design. It is made up of 800(160x5) SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 512MB		75 Watts
Radeon HD 4850 1GB		110 Watts
	Difference: 35 Watts (47%)

Memory Bandwidth

The Radeon HD 4850 1GB, in theory, should be a bit faster than the Radeon HD 3850 512MB overall. (explain)

Radeon HD 4850 1GB		63552 MB/sec
Radeon HD 3850 512MB		52992 MB/sec
	Difference: 10560 (20%)

Texel Rate

The Radeon HD 4850 1GB is much (approximately 134%) more effective at texture filtering than the Radeon HD 3850 512MB. (explain)

Radeon HD 4850 1GB		25000 Mtexels/sec
Radeon HD 3850 512MB		10688 Mtexels/sec
	Difference: 14312 (134%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 3850 512MB is superior to the Radeon HD 4850 1GB, but only just. (explain)

Radeon HD 3850 512MB		10688 Mpixels/sec
Radeon HD 4850 1GB		10000 Mpixels/sec
	Difference: 688 (7%)

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 information (in units of megabytes per second) that can be transported past the external memory interface within a second. It is calculated by multiplying the bus width by its memory clock speed. In the case of DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.