Radeon HD 4770 vs Radeon HD 7790

Intro

Compare those specifications to the Radeon HD 7790, which comes with GPU core speed of 1000 MHz, and 1024 MB of GDDR5 memory running at 1500 MHz through a 128-bit bus. It also is comprised of 896 Stream Processors, 56 TAUs, and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
Radeon HD 7790		85 Watts
	Difference: 5 Watts (6%)

Memory Bandwidth

Performance-wise, the Radeon HD 7790 should in theory be quite a bit better than the Radeon HD 4770 in general. (explain)

Radeon HD 7790		96000 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 44800 (88%)

Texel Rate

The Radeon HD 7790 will be a lot (about 133%) faster with regards to anisotropic filtering than the Radeon HD 4770. (explain)

Radeon HD 7790		56000 Mtexels/sec
Radeon HD 4770		24000 Mtexels/sec
	Difference: 32000 (133%)

Pixel Rate

The Radeon HD 7790 will be quite a bit (more or less 33%) better at AA than the Radeon HD 4770, and should be able to handle higher resolutions more effectively. (explain)

Radeon HD 7790		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: Memory bandwidth is the max amount of information (measured in MB per second) that can be moved across the external memory interface in a second. The number is worked out by multiplying the card's interface width by the speed of its memory. If the card has DDR RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high 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 the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly write to the local memory in a 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 called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.