GeForce 840M vs Radeon R9 M395X

Intro

Compare those specifications to the Radeon R9 M395X, which features a core clock frequency of 723 MHz and a GDDR5 memory frequency of 1250 MHz. It also features a 256-bit bus, and makes use of a 28 nm design. It is comprised of 2048 SPUs, 128 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 840M		30 Watts
Radeon R9 M395X		125 Watts
	Difference: 95 Watts (317%)

Memory Bandwidth

The Radeon R9 M395X should theoretically perform a lot faster than the GeForce 840M in general. (explain)

Radeon R9 M395X		160000 MB/sec
GeForce 840M		16000 MB/sec
	Difference: 144000 (900%)

Texel Rate

The Radeon R9 M395X is a lot (more or less 275%) better at texture filtering than the GeForce 840M. (explain)

Radeon R9 M395X		92544 Mtexels/sec
GeForce 840M		24696 Mtexels/sec
	Difference: 67848 (275%)

Pixel Rate

The Radeon R9 M395X is a lot (approximately 181%) better at AA than the GeForce 840M, and should be able to handle higher resolutions without losing too much performance. (explain)

Radeon R9 M395X		23136 Mpixels/sec
GeForce 840M		8232 Mpixels/sec
	Difference: 14904 (181%)

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 maximum amount of information (measured in MB per second) that can be transported over the external memory interface in one second. It is calculated by multiplying the bus width by its memory speed. If it uses DDR memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant 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.