GeForce GTX 850M vs Radeon HD 4870 2GB

Intro

Compare those specs to the Radeon HD 4870 2GB, which makes use of a 55 nm design. AMD has clocked the core frequency at 750 MHz. The GDDR5 memory runs at a speed of 900 MHz on this particular card. It features 800(160x5) SPUs along with 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 4870 2GB		150 Watts
	Difference: 110 Watts (275%)

Memory Bandwidth

The Radeon HD 4870 2GB should in theory perform quite a bit faster than the GeForce GTX 850M in general. (explain)

Radeon HD 4870 2GB		115200 MB/sec
GeForce GTX 850M		32000 MB/sec
	Difference: 83200 (260%)

Texel Rate

The GeForce GTX 850M should be a bit (more or less 17%) faster with regards to AF than the Radeon HD 4870 2GB. (explain)

GeForce GTX 850M		35040 Mtexels/sec
Radeon HD 4870 2GB		30000 Mtexels/sec
	Difference: 5040 (17%)

Pixel Rate

The GeForce GTX 850M is a small bit (about 17%) better at FSAA than the Radeon HD 4870 2GB, and should be capable of handling higher screen resolutions without slowing down too much. (explain)

GeForce GTX 850M		14016 Mpixels/sec
Radeon HD 4870 2GB		12000 Mpixels/sec
	Difference: 2016 (17%)

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 maximum amount of information (in units of MB per second) that can be transferred over the external memory interface in a second. It's calculated by multiplying the interface width by its memory clock speed. If the card has DDR RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, 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 texture map elements (texels) that can be processed in one second. This is calculated by multiplying the total texture units of the card by the core clock 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 per second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly write to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel 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 ability to reach the maximum fill rate.