Radeon HD 4890 1GB vs Radeon HD 5770

Intro

Compare all that to the Radeon HD 5770, which makes use of a 40 nm design. AMD has set the core frequency at 850 MHz. The GDDR5 RAM works at a frequency of 1200 MHz on this particular card. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 5770		108 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 82 Watts (76%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4890 1GB should be a lot faster than the Radeon HD 5770 in general. (explain)

Radeon HD 4890 1GB		124800 MB/sec
Radeon HD 5770		76800 MB/sec
	Difference: 48000 (63%)

Texel Rate

The Radeon HD 4890 1GB will be a bit (approximately 18%) better at anisotropic filtering than the Radeon HD 5770. (explain)

Radeon HD 4890 1GB		40000 Mtexels/sec
Radeon HD 5770		34000 Mtexels/sec
	Difference: 6000 (18%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 4890 1GB is the winner, though only just barely. (explain)

Radeon HD 4890 1GB		16000 Mpixels/sec
Radeon HD 5770		13600 Mpixels/sec
	Difference: 2400 (18%)

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 maximum amount of information (in units of megabytes per second) that can be transferred over the external memory interface within a second. It is worked out by multiplying the bus width by its memory clock speed. If the card has DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the card's 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 amount of texture map elements (texels) that are applied in one second. This number is calculated by multiplying the total texture units by the core speed of the chip. The higher this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.