Radeon HD 4770 vs Radeon HD 5770

Intro

Compare those specifications to the Radeon HD 5770, which comes with a clock frequency of 850 MHz and a GDDR5 memory speed of 1200 MHz. It also features a 128-bit bus, and uses a 40 nm design. It is comprised of 800(160x5) SPUs, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
Radeon HD 5770		108 Watts
	Difference: 28 Watts (35%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 5770 should perform quite a bit faster than the Radeon HD 4770 overall. (explain)

Radeon HD 5770		76800 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 25600 (50%)

Texel Rate

The Radeon HD 5770 will be quite a bit (about 42%) faster with regards to anisotropic filtering than the Radeon HD 4770. (explain)

Radeon HD 5770		34000 Mtexels/sec
Radeon HD 4770		24000 Mtexels/sec
	Difference: 10000 (42%)

Pixel Rate

The Radeon HD 5770 is a small bit (approximately 13%) better at full screen anti-aliasing than the Radeon HD 4770, and will be capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon HD 5770		13600 Mpixels/sec
Radeon HD 4770		12000 Mpixels/sec
	Difference: 1600 (13%)

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 data (measured in MB per second) that can be transported over the external memory interface within a second. It's worked out by multiplying the bus width by its memory speed. If the card has DDR type memory, it must be multiplied by 2 once 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, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on 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 ability to get to the max fill rate.