Radeon HD 4650 512MB vs Radeon HD 6670 (OEM) 1GB

Intro

Compare all of that to the Radeon HD 6670 (OEM) 1GB, which features a clock frequency of 800 MHz and a GDDR5 memory speed of 1000 MHz. It also uses a 128-bit memory bus, and makes use of a 40 nm design. It is comprised of 480 SPUs, 24 TAUs, and 8 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 512MB		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 theoretically be a lot superior to the Radeon HD 4650 512MB in general. (explain)

Radeon HD 6670 (OEM) 1GB		64000 MB/sec
Radeon HD 4650 512MB		16000 MB/sec
	Difference: 48000 (300%)

Texel Rate

Both cards have exactly the same texel rate, so theoretically they should be equally good at at AF. (explain)

Pixel Rate

The Radeon HD 6670 (OEM) 1GB is quite a bit (about 33%) faster with regards to FSAA than the Radeon HD 4650 512MB, and should be capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 6670 (OEM) 1GB		6400 Mpixels/sec
Radeon HD 4650 512MB		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 maximum amount of data (in units of megabytes per second) that can be moved across the external memory interface within a second. It's calculated by multiplying the interface width by its memory clock speed. In the case of DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This number is worked out by multiplying the total amount of texture units by the core speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.