Radeon HD 3850 512MB vs Radeon HD 4650 1GB

Intro

Compare that to the Radeon HD 4650 1GB, which makes use of a 55 nm design. AMD has clocked the core frequency at 600 MHz. The GDDR3 RAM runs at a speed of 700 MHz on this specific card. It features 320(64x5) SPUs as well as 32 Texture Address Units and 8 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 1GB		55 Watts
Radeon HD 3850 512MB		75 Watts
	Difference: 20 Watts (36%)

Memory Bandwidth

As far as performance goes, the Radeon HD 3850 512MB should theoretically be a lot better than the Radeon HD 4650 1GB overall. (explain)

Radeon HD 3850 512MB		52992 MB/sec
Radeon HD 4650 1GB		22400 MB/sec
	Difference: 30592 (137%)

Texel Rate

The Radeon HD 4650 1GB will be quite a bit (approximately 80%) better at texture filtering than the Radeon HD 3850 512MB. (explain)

Radeon HD 4650 1GB		19200 Mtexels/sec
Radeon HD 3850 512MB		10688 Mtexels/sec
	Difference: 8512 (80%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 3850 512MB is superior to the Radeon HD 4650 1GB, by far. (explain)

Radeon HD 3850 512MB		10688 Mpixels/sec
Radeon HD 4650 1GB		4800 Mpixels/sec
	Difference: 5888 (123%)

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 (in units of MB per second) that can be transferred over the external memory interface within a second. It is worked out by multiplying the interface width by the speed of its memory. If the card has DDR type RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly write to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of colour ROPs 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 output rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.