Radeon HD 3650 256MB vs Radeon HD 4650 1GB

Intro

Compare those specs to the Radeon HD 4650 1GB, which uses a 55 nm design. AMD has clocked the core speed 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 3650 256MB		78 Watts
	Difference: 23 Watts (42%)

Memory Bandwidth

The Radeon HD 3650 256MB should in theory perform just a bit faster than the Radeon HD 4650 1GB in general. (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 should be a lot (approximately 231%) more effective at texture 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 (approximately 66%) faster with regards to anti-aliasing than the Radeon HD 3650 256MB, and also should be capable of handling higher screen resolutions while still performing well. (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 largest amount of information (counted in MB per second) that can be moved past the external memory interface in a second. The number is worked out by multiplying the interface width by its memory speed. In the case of DDR type RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This number is worked out by multiplying the total amount of texture units 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 per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.