GeForce 820M vs Radeon HD 7770

Intro

Compare those specs to the Radeon HD 7770, which uses a 28 nm design. AMD has clocked the core frequency at 1000 MHz. The GDDR5 RAM runs at a speed of 1125 MHz on this particular model. It features 640 SPUs along with 40 TAUs and 16 ROPs.

Display Graphs

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Benchmarks

These are real-world performance benchmarks that were submitted by Hardware Compare users. The scores seen here are the average of all benchmarks submitted for each respective test and hardware.

3DMark Fire Strike Graphics Score

Radeon HD 7770		3180 points
GeForce 820M		850 points
	Difference: 2330 (274%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
Radeon HD 7770		80 Watts
	Difference: 65 Watts (433%)

Memory Bandwidth

The Radeon HD 7770, in theory, should be quite a bit faster than the GeForce 820M overall. (explain)

Radeon HD 7770		72000 MB/sec
GeForce 820M		16000 MB/sec
	Difference: 56000 (350%)

Texel Rate

The Radeon HD 7770 should be a lot (approximately 248%) more effective at anisotropic filtering than the GeForce 820M. (explain)

Radeon HD 7770		40000 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 28496 (248%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 7770 is the winner, and very much so. (explain)

Radeon HD 7770		16000 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 13124 (456%)

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 data (measured in MB per second) that can be transported past the external memory interface in one second. The number is calculated by multiplying the card's interface width by the speed of its memory. In the case of DDR memory, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly record to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the core clock speed. 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 - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.