Radeon HD 4870 1GB vs Radeon HD 6790

Intro

Compare those specifications to the Radeon HD 6790, which has core speeds of 840 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 memory. It features 800 SPUs along with 40 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Both cards have the same power consumption.

Memory Bandwidth

Performance-wise, the Radeon HD 6790 should theoretically be a little bit better than the Radeon HD 4870 1GB in general. (explain)

Radeon HD 6790		134400 MB/sec
Radeon HD 4870 1GB		115200 MB/sec
	Difference: 19200 (17%)

Texel Rate

The Radeon HD 6790 is a small bit (approximately 12%) more effective at texture filtering than the Radeon HD 4870 1GB. (explain)

Radeon HD 6790		33600 Mtexels/sec
Radeon HD 4870 1GB		30000 Mtexels/sec
	Difference: 3600 (12%)

Pixel Rate

The Radeon HD 6790 will be a bit (about 12%) more effective at AA than the Radeon HD 4870 1GB, and also capable of handling higher screen resolutions while still performing well. (explain)

Radeon HD 6790		13440 Mpixels/sec
Radeon HD 4870 1GB		12000 Mpixels/sec
	Difference: 1440 (12%)

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 (counted in megabytes per second) that can be transferred past the external memory interface within a second. It is worked out by multiplying the interface width by the speed of its memory. In the case of DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly record to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.