GeForce 820M vs Radeon HD 4650 512MB

Intro

Compare all of that to the Radeon HD 4650 512MB, which comes with GPU clock speed of 600 MHz, and 512 MB of DDR2 memory set to run at 500 MHz through a 128-bit bus. It also is made up of 320(64x5) Stream Processors, 32 TAUs, and 8 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
Radeon HD 4650 512MB		55 Watts
	Difference: 40 Watts (267%)

Memory Bandwidth

Both cards have the exact same memory bandwidth, so theoretically they should have identical performance. (explain)

Texel Rate

The Radeon HD 4650 512MB is quite a bit (more or less 67%) better at anisotropic filtering than the GeForce 820M. (explain)

Radeon HD 4650 512MB		19200 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 7696 (67%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 4650 512MB is the winner, and very much so. (explain)

Radeon HD 4650 512MB		4800 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 1924 (67%)

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 maximum amount of information (in units of MB per second) that can be transferred across the external memory interface in one second. It's calculated by multiplying the bus width by the speed of its memory. In the case of DDR type RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied in one second. This is worked out by multiplying the total amount of texture units of the card by the core 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 that the graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.