Radeon HD 4890 1GB vs Radeon HD 5770

Intro

Compare those specifications to the Radeon HD 5770, which makes use of a 40 nm design. AMD has set the core frequency at 850 MHz. The GDDR5 memory runs at a speed of 1200 MHz on this particular model. It features 800(160x5) SPUs along with 40 Texture Address Units 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

The Radeon HD 4890 1GB should in theory perform much faster than the Radeon HD 5770 overall. (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%) more effective at texture 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

The Radeon HD 4890 1GB is just a bit (more or less 18%) better at full screen anti-aliasing than the Radeon HD 5770, and should be able to handle higher resolutions without losing too much performance. (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: Bandwidth is the largest amount of data (counted in megabytes per second) that can be moved across the external memory interface within a second. It's calculated by multiplying the card's bus width by the speed of its memory. If the card has DDR memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly record to the local memory per 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 - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.