GeForce 840M vs Radeon HD 4650 512MB

Intro

Compare those specifications to the Radeon HD 4650 512MB, which uses a 55 nm design. AMD has clocked the core speed at 600 MHz. The DDR2 memory is set to run at a frequency of 500 MHz on this specific card. It features 320(64x5) SPUs along with 32 Texture Address Units and 8 Rasterization Operator 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 exactly the same bandwidth, so in theory they should have the same performance. (explain)

Texel Rate

The GeForce 840M should be much (approximately 29%) faster with regards to 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 max amount of data (in units of megabytes per second) that can be moved past the external memory interface in a second. It's calculated by multiplying the bus width by its memory speed. If the card has DDR type memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to the local memory in one 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 output rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.