GeForce 840M vs Radeon HD 4650 512MB

Intro

Compare all that to the Radeon HD 4650 512MB, which comes with a core clock speed of 600 MHz and a DDR2 memory speed of 500 MHz. It also uses a 128-bit memory bus, and uses a 55 nm design. It is comprised of 320(64x5) SPUs, 32 Texture Address Units, and 8 Raster Operation Units.

Display Graphs

Hide Graphs

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 bandwidth, so in theory they should have the same performance. (explain)

Texel Rate

The GeForce 840M should be a lot (about 29%) faster with regards to texture filtering 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 a high screen resolution is important to you, then the GeForce 840M is a better choice, 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: Bandwidth is the maximum amount of information (counted in megabytes per second) that can be transported over the external memory interface within a second. It's calculated by multiplying the card's bus width by its memory speed. In the case of DDR memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

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

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