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

Intro

Compare all that to the Radeon HD 6670 (OEM) 1GB, which features GPU core speed of 800 MHz, and 1024 MB of GDDR5 memory running at 1000 MHz through a 128-bit bus. It also is comprised of 480 Stream Processors, 24 Texture Address Units, and 8 Raster Operation Units.

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

As far as performance goes, the Radeon HD 6670 (OEM) 1GB should in theory be much superior to 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 exactly the same texel fill rate, so theoretically they should be equally good at at AF. (explain)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 6670 (OEM) 1GB is superior to the Radeon HD 4650 1GB, by far. (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 max amount of data (in units of MB per second) that can be moved across the external memory interface in one second. It is worked out by multiplying the card's bus width by the speed of its memory. In the case of DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This is worked out 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 graphics card will be at 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 that the graphics chip could possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.