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 memory bus, and makes use of a 40 nm design. It is made up of 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 should theoretically perform much faster than the Radeon HD 4650 1GB overall. (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 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 megabytes per second) that can be transported past the external memory interface within a second. It is calculated by multiplying the interface width by the speed of its memory. In the case of DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the video 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 the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.