Radeon HD 4650 1GB vs Radeon HD 6670 (OEM) 1GB

Intro

Compare those specifications to the Radeon HD 6670 (OEM) 1GB, which features a core clock frequency of 800 MHz and a GDDR5 memory frequency of 1000 MHz. It also uses a 128-bit bus, and makes use of a 40 nm design. It features 480 SPUs, 24 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 6670 (OEM) 1GB		63 Watts
	Difference: 8 Watts (15%)

Memory Bandwidth

The Radeon HD 6670 (OEM) 1GB, in theory, should be a lot faster than the Radeon HD 4650 1GB in general. (explain)

Radeon HD 6670 (OEM) 1GB		64000 MB/sec
Radeon HD 4650 1GB		22400 MB/sec
	Difference: 41600 (186%)

Texel Rate

Both cards have the exact same texel rate, so in theory they should perform equally good at at AF. (explain)

Pixel Rate

The Radeon HD 6670 (OEM) 1GB is quite a bit (more or less 33%) faster with regards to AA than the Radeon HD 4650 1GB, and able to handle higher resolutions without slowing down too much. (explain)

Radeon HD 6670 (OEM) 1GB		6400 Mpixels/sec
Radeon HD 4650 1GB		4800 Mpixels/sec
	Difference: 1600 (33%)

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 data (in units of megabytes per second) that can be moved over the external memory interface in a second. It's calculated by multiplying the interface width by its memory clock speed. In the case of DDR type RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This is worked out by multiplying the total texture units by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at handling 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 the graphics card could possibly record to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the core clock speed. 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 rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.