GeForce 820M vs Radeon HD 4870 2GB

Intro

Compare all that to the Radeon HD 4870 2GB, which makes use of a 55 nm design. AMD has set the core speed at 750 MHz. The GDDR5 memory works at a speed of 900 MHz on this specific card. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
Radeon HD 4870 2GB		150 Watts
	Difference: 135 Watts (900%)

Memory Bandwidth

Performance-wise, the Radeon HD 4870 2GB should theoretically be much superior to the GeForce 820M overall. (explain)

Radeon HD 4870 2GB		115200 MB/sec
GeForce 820M		16000 MB/sec
	Difference: 99200 (620%)

Texel Rate

The Radeon HD 4870 2GB is a lot (more or less 161%) faster with regards to AF than the GeForce 820M. (explain)

Radeon HD 4870 2GB		30000 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 18496 (161%)

Pixel Rate

The Radeon HD 4870 2GB should be quite a bit (about 317%) more effective at anti-aliasing than the GeForce 820M, and also should be capable of handling higher screen resolutions while still performing well. (explain)

Radeon HD 4870 2GB		12000 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 9124 (317%)

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 max amount of information (in units of MB per second) that can be moved past the external memory interface in one second. It's calculated by multiplying the card's interface width by the speed of its memory. If the card has DDR type memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the faster 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 applied in one second. This number is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The higher this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.