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

Intro

Compare all of that to the Radeon HD 6670 (OEM), which has GPU clock speed of 800 MHz, and 512 MB of GDDR5 RAM running at 1000 MHz through a 128-bit bus. It also features 480 Stream Processors, 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)		63 Watts
	Difference: 8 Watts (15%)

Memory Bandwidth

In theory, the Radeon HD 6670 (OEM) should be 186% quicker than the Radeon HD 4650 1GB in general, due to its higher bandwidth. (explain)

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

Texel Rate

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

Pixel Rate

The Radeon HD 6670 (OEM) should be quite a bit (about 33%) more effective at FSAA than the Radeon HD 4650 1GB, and also should be capable of handling higher screen resolutions without slowing down too much. (explain)

Radeon HD 6670 (OEM)		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: Memory bandwidth is the largest amount of data (measured in megabytes per second) that can be transported across the external memory interface within a second. It's calculated by multiplying the card's bus width by its memory clock speed. If the card has DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This figure is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better this number, the better the graphics 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 amount of pixels that the graphics chip could possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.