GeForce 840M vs Radeon R9 M265X

Intro

Compare those specs to the Radeon R9 M265X, which has core clock speeds of 575 MHz on the GPU, and 1125 MHz on the 2048 MB of GDDR5 memory. It features 640 SPUs along with 40 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon R9 M265X will be 350% quicker than the GeForce 840M overall, because of its higher bandwidth. (explain)

Radeon R9 M265X		72000 MB/sec
GeForce 840M		16000 MB/sec
	Difference: 56000 (350%)

Texel Rate

The GeForce 840M is a little bit (approximately 7%) faster with regards to anisotropic filtering than the Radeon R9 M265X. (explain)

GeForce 840M		24696 Mtexels/sec
Radeon R9 M265X		23000 Mtexels/sec
	Difference: 1696 (7%)

Pixel Rate

The Radeon R9 M265X will be just a bit (about 12%) more effective at anti-aliasing than the GeForce 840M, and will be capable of handling higher resolutions while still performing well. (explain)

Radeon R9 M265X		9200 Mpixels/sec
GeForce 840M		8232 Mpixels/sec
	Difference: 968 (12%)

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 largest amount of data (in units of MB per second) that can be transported across the external memory interface within a second. It's calculated by multiplying the card's interface width by the speed of its memory. If it uses DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, 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 amount of texture map elements (texels) that are processed per second. This is calculated by multiplying the total number of texture units 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 per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.