Radeon HD 4850 1GB vs Radeon HD 7770

Intro

Compare that to the Radeon HD 7770, which has a clock speed of 1000 MHz and a GDDR5 memory frequency of 1125 MHz. It also uses a 128-bit bus, and makes use of a 28 nm design. It is made up of 640 SPUs, 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 1GB		110 Watts
	Difference: 30 Watts (38%)

Memory Bandwidth

In theory, the Radeon HD 7770 will be 13% faster than the Radeon HD 4850 1GB in general, due to its greater bandwidth. (explain)

Radeon HD 7770		72000 MB/sec
Radeon HD 4850 1GB		63552 MB/sec
	Difference: 8448 (13%)

Texel Rate

The Radeon HD 7770 should be a lot (approximately 60%) faster with regards to anisotropic filtering than the Radeon HD 4850 1GB. (explain)

Radeon HD 7770		40000 Mtexels/sec
Radeon HD 4850 1GB		25000 Mtexels/sec
	Difference: 15000 (60%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 7770 is the winner, and very much so. (explain)

Radeon HD 7770		16000 Mpixels/sec
Radeon HD 4850 1GB		10000 Mpixels/sec
	Difference: 6000 (60%)

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 (measured in megabytes per second) that can be moved past the external memory interface within a second. It is calculated by multiplying the interface width by its memory clock speed. If the card has DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly write to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.