Radeon HD 3650 256MB 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 works at a speed of 700 MHz on this 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 3650 256MB		78 Watts
	Difference: 23 Watts (42%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 3650 256MB is 14% quicker than the Radeon HD 4650 1GB overall, due to its higher bandwidth. (explain)

Radeon HD 3650 256MB		25600 MB/sec
Radeon HD 4650 1GB		22400 MB/sec
	Difference: 3200 (14%)

Texel Rate

The Radeon HD 4650 1GB is quite a bit (approximately 231%) faster with regards to anisotropic filtering than the Radeon HD 3650 256MB. (explain)

Radeon HD 4650 1GB		19200 Mtexels/sec
Radeon HD 3650 256MB		5800 Mtexels/sec
	Difference: 13400 (231%)

Pixel Rate

The Radeon HD 4650 1GB should be much (about 66%) more effective at AA than the Radeon HD 3650 256MB, and will be able to handle higher resolutions better. (explain)

Radeon HD 4650 1GB		4800 Mpixels/sec
Radeon HD 3650 256MB		2900 Mpixels/sec
	Difference: 1900 (66%)

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 maximum amount of information (counted in megabytes per second) that can be transferred over the external memory interface within a second. The number is calculated by multiplying the bus width by the speed of its memory. If it uses DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better 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 number of texture map elements (texels) that are processed in one second. This figure is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to 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 maximum fill rate.