GeForce 840M vs Radeon R9 M290X

Intro

Compare that to the Radeon R9 M290X, which comes with a core clock frequency of 850 MHz and a GDDR5 memory frequency of 1200 MHz. It also makes use of a 256-bit bus, and makes use of a 28 nm design. It is made up of 1280 SPUs, 80 Texture Address Units, and 32 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 840M		30 Watts
Radeon R9 M290X		100 Watts
	Difference: 70 Watts (233%)

Memory Bandwidth

In theory, the Radeon R9 M290X is 860% quicker than the GeForce 840M in general, because of its greater data rate. (explain)

Radeon R9 M290X		153600 MB/sec
GeForce 840M		16000 MB/sec
	Difference: 137600 (860%)

Texel Rate

The Radeon R9 M290X should be quite a bit (more or less 175%) better at anisotropic filtering than the GeForce 840M. (explain)

Radeon R9 M290X		68000 Mtexels/sec
GeForce 840M		24696 Mtexels/sec
	Difference: 43304 (175%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon R9 M290X is the winner, by far. (explain)

Radeon R9 M290X		27200 Mpixels/sec
GeForce 840M		8232 Mpixels/sec
	Difference: 18968 (230%)

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 max amount of information (in units of MB per second) that can be moved over the external memory interface in a second. It's worked out by multiplying the bus width by the speed of its memory. In the case of DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the better 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 texture map elements (texels) that can be applied per second. This figure is calculated by multiplying the total number of texture units by the core clock speed of the chip. The higher the texel rate, the better the graphics 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 its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.