Radeon HD 4770 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 running at 1125 MHz through a 128-bit bus. It also is made up of 640 SPUs, 40 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Both cards have the same power consumption.

Memory Bandwidth

Theoretically speaking, the Radeon HD 7770 should perform much faster than the Radeon HD 4770 overall. (explain)

Radeon HD 7770		72000 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 20800 (41%)

Texel Rate

The Radeon HD 7770 should be a lot (approximately 67%) more effective at texture filtering than the Radeon HD 4770. (explain)

Radeon HD 7770		40000 Mtexels/sec
Radeon HD 4770		24000 Mtexels/sec
	Difference: 16000 (67%)

Pixel Rate

The Radeon HD 7770 is quite a bit (more or less 33%) faster with regards to AA than the Radeon HD 4770, and also should be able to handle higher resolutions while still performing well. (explain)

Radeon HD 7770		16000 Mpixels/sec
Radeon HD 4770		12000 Mpixels/sec
	Difference: 4000 (33%)

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 information (in units of MB 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 clock speed. In the case of DDR memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. 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 per second. This number is calculated by multiplying the total amount of texture units of the card 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 in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.