Radeon HD 4870 X2 vs Radeon HD 7770

Intro

Compare that to the Radeon HD 7770, which makes use of a 28 nm design. AMD has clocked the core speed at 1000 MHz. The GDDR5 memory runs at a frequency of 1125 MHz on this specific card. It features 640 SPUs as well as 40 Texture Address Units and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7770		80 Watts
Radeon HD 4870 X2		350 Watts
	Difference: 270 Watts (338%)

Memory Bandwidth

The Radeon HD 4870 X2 should in theory perform a lot faster than the Radeon HD 7770 in general. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon HD 7770		72000 MB/sec
	Difference: 158400 (220%)

Texel Rate

The Radeon HD 4870 X2 is a lot (about 50%) better at texture filtering than the Radeon HD 7770. (explain)

Radeon HD 4870 X2		60000 Mtexels/sec
Radeon HD 7770		40000 Mtexels/sec
	Difference: 20000 (50%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 4870 X2 is a better choice, and very much so. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
Radeon HD 7770		16000 Mpixels/sec
	Difference: 8000 (50%)

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: Bandwidth is the maximum amount of data (measured in megabytes per second) that can be moved past the external memory interface within a second. It is worked out by multiplying the interface width by its memory speed. If the card has DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels the video card could possibly write to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of Raster Operations Pipelines by the the core 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 also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.