GeForce GTX 850M vs Radeon HD 4890 2GB

Intro

Compare all that to the Radeon HD 4890 2GB, which features core speeds of 1000 MHz on the GPU, and 975 MHz on the 2048 MB of GDDR5 RAM. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 850M		40 Watts
Radeon HD 4890 2GB		190 Watts
	Difference: 150 Watts (375%)

Memory Bandwidth

The Radeon HD 4890 2GB should theoretically perform much faster than the GeForce GTX 850M in general. (explain)

Radeon HD 4890 2GB		124800 MB/sec
GeForce GTX 850M		32000 MB/sec
	Difference: 92800 (290%)

Texel Rate

The Radeon HD 4890 2GB will be a small bit (approximately 14%) faster with regards to texture filtering than the GeForce GTX 850M. (explain)

Radeon HD 4890 2GB		40000 Mtexels/sec
GeForce GTX 850M		35040 Mtexels/sec
	Difference: 4960 (14%)

Pixel Rate

The Radeon HD 4890 2GB should be just a bit (about 14%) better at AA than the GeForce GTX 850M, and also should be able to handle higher screen resolutions without losing too much performance. (explain)

Radeon HD 4890 2GB		16000 Mpixels/sec
GeForce GTX 850M		14016 Mpixels/sec
	Difference: 1984 (14%)

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 largest amount of data (measured in MB per second) that can be transferred across the external memory interface in a second. It's calculated by multiplying the bus width by its memory clock speed. If it uses DDR RAM, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly write to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.