GeForce 8400 GS 512MB vs Radeon HD 6770

Intro

Compare those specifications to the Radeon HD 6770, which has a clock frequency of 900 MHz and a GDDR5 memory speed of 1050 MHz. It also uses a 128-bit bus, and uses a 40 nm design. It is made up of 800 SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8400 GS 512MB		40 Watts
Radeon HD 6770		108 Watts
	Difference: 68 Watts (170%)

Memory Bandwidth

Performance-wise, the Radeon HD 6770 should in theory be quite a bit superior to the GeForce 8400 GS 512MB in general. (explain)

Radeon HD 6770		67200 MB/sec
GeForce 8400 GS 512MB		6400 MB/sec
	Difference: 60800 (950%)

Texel Rate

The Radeon HD 6770 will be quite a bit (more or less 592%) more effective at anisotropic filtering than the GeForce 8400 GS 512MB. (explain)

Radeon HD 6770		36000 Mtexels/sec
GeForce 8400 GS 512MB		5200 Mtexels/sec
	Difference: 30800 (592%)

Pixel Rate

The Radeon HD 6770 is a lot (approximately 454%) better at full screen anti-aliasing than the GeForce 8400 GS 512MB, and should be capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon HD 6770		14400 Mpixels/sec
GeForce 8400 GS 512MB		2600 Mpixels/sec
	Difference: 11800 (454%)

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 largest amount of information (counted in MB per second) that can be transported over the external memory interface in a second. It is worked out by multiplying the interface width by its memory speed. If the card has DDR type memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster 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 texture map elements (texels) that are processed per second. This number is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The higher this number, the better the graphics 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 amount of pixels that the graphics chip could possibly write to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.