Radeon HD 4850 X2 512MB vs Radeon HD 7770

Intro

Compare that to the Radeon HD 7770, which has a GPU core clock speed of 1000 MHz, and 1024 MB of GDDR5 RAM set to run at 1125 MHz through a 128-bit bus. It also is comprised of 640 Stream Processors, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7770		80 Watts
Radeon HD 4850 X2 512MB		250 Watts
	Difference: 170 Watts (213%)

Memory Bandwidth

The Radeon HD 4850 X2 512MB should in theory perform a lot faster than the Radeon HD 7770 overall. (explain)

Radeon HD 4850 X2 512MB		127104 MB/sec
Radeon HD 7770		72000 MB/sec
	Difference: 55104 (77%)

Texel Rate

The Radeon HD 4850 X2 512MB will be a lot (more or less 25%) faster with regards to anisotropic filtering than the Radeon HD 7770. (explain)

Radeon HD 4850 X2 512MB		50000 Mtexels/sec
Radeon HD 7770		40000 Mtexels/sec
	Difference: 10000 (25%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 4850 X2 512MB is a better choice, by a large margin. (explain)

Radeon HD 4850 X2 512MB		20000 Mpixels/sec
Radeon HD 7770		16000 Mpixels/sec
	Difference: 4000 (25%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the maximum amount of information (measured in MB per second) that can be moved over the external memory interface in a second. It's worked out by multiplying the interface width by the speed of its memory. If it uses DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This figure is worked out by multiplying the total 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 in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can 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 ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.