GeForce 840M vs Radeon HD 4650 512MB

Intro

Compare those specs to the Radeon HD 4650 512MB, which has a GPU core clock speed of 600 MHz, and 512 MB of DDR2 memory running at 500 MHz through a 128-bit bus. It also is comprised of 320(64x5) Stream Processors, 32 Texture Address Units, and 8 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 840M		30 Watts
Radeon HD 4650 512MB		55 Watts
	Difference: 25 Watts (83%)

Memory Bandwidth

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

Texel Rate

The GeForce 840M will be much (approximately 29%) better at AF than the Radeon HD 4650 512MB. (explain)

GeForce 840M		24696 Mtexels/sec
Radeon HD 4650 512MB		19200 Mtexels/sec
	Difference: 5496 (29%)

Pixel Rate

If using high levels of AA is important to you, then the GeForce 840M is the winner, by far. (explain)

GeForce 840M		8232 Mpixels/sec
Radeon HD 4650 512MB		4800 Mpixels/sec
	Difference: 3432 (72%)

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 information (measured in megabytes per second) that can be transferred past the external memory interface in a second. The number is worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR type memory, the result should be multiplied by 2 once 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 amount of texture map elements (texels) that are applied in one second. This is worked out by multiplying the total number of texture units by the core clock speed of the chip. The better this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the amount of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.