GeForce 820M vs Radeon HD 4770

Intro

Compare all that to the Radeon HD 4770, which has core speeds of 750 MHz on the GPU, and 800 MHz on the 512 MB of GDDR5 memory. It features 640(128x5) SPUs along with 32 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
Radeon HD 4770		80 Watts
	Difference: 65 Watts (433%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4770 should in theory be much superior to the GeForce 820M in general. (explain)

Radeon HD 4770		51200 MB/sec
GeForce 820M		16000 MB/sec
	Difference: 35200 (220%)

Texel Rate

The Radeon HD 4770 is a lot (approximately 109%) faster with regards to anisotropic filtering than the GeForce 820M. (explain)

Radeon HD 4770		24000 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 12496 (109%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 4770 is the winner, and very much so. (explain)

Radeon HD 4770		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: Bandwidth is the largest amount of information (measured in megabytes per second) that can be transported across the external memory interface within a second. The number is worked out by multiplying the interface width by its memory speed. If it uses DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.