GeForce 8400 GS 512MB vs Radeon HD 7770

Intro

Compare all that to the Radeon HD 7770, which comes with a clock speed of 1000 MHz and a GDDR5 memory frequency of 1125 MHz. It also features a 128-bit memory bus, and uses a 28 nm design. It features 640 SPUs, 40 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8400 GS 512MB		40 Watts
Radeon HD 7770		80 Watts
	Difference: 40 Watts (100%)

Memory Bandwidth

The Radeon HD 7770 should in theory be a lot faster than the GeForce 8400 GS 512MB in general. (explain)

Radeon HD 7770		72000 MB/sec
GeForce 8400 GS 512MB		6400 MB/sec
	Difference: 65600 (1025%)

Texel Rate

The Radeon HD 7770 should be a lot (approximately 669%) faster with regards to AF than the GeForce 8400 GS 512MB. (explain)

Radeon HD 7770		40000 Mtexels/sec
GeForce 8400 GS 512MB		5200 Mtexels/sec
	Difference: 34800 (669%)

Pixel Rate

The Radeon HD 7770 will be a lot (approximately 515%) more effective at full screen anti-aliasing than the GeForce 8400 GS 512MB, and will be able to handle higher resolutions better. (explain)

Radeon HD 7770		16000 Mpixels/sec
GeForce 8400 GS 512MB		2600 Mpixels/sec
	Difference: 13400 (515%)

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 data (counted in megabytes per second) that can be transported past the external memory interface in a second. It's calculated by multiplying the bus width by its memory speed. In the case of DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.