Radeon HD 3870 1GB vs Radeon HD 7790

Intro

Compare those specs to the Radeon HD 7790, which features a GPU core clock speed of 1000 MHz, and 1024 MB of GDDR5 RAM running at 1500 MHz through a 128-bit bus. It also is made up of 896 SPUs, 56 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7790		85 Watts
Radeon HD 3870 1GB		106 Watts
	Difference: 21 Watts (25%)

Memory Bandwidth

In theory, the Radeon HD 7790 should be quite a bit faster than the Radeon HD 3870 1GB in general. (explain)

Radeon HD 7790		96000 MB/sec
Radeon HD 3870 1GB		72000 MB/sec
	Difference: 24000 (33%)

Texel Rate

The Radeon HD 7790 is a lot (approximately 352%) more effective at anisotropic filtering than the Radeon HD 3870 1GB. (explain)

Radeon HD 7790		56000 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 43600 (352%)

Pixel Rate

The Radeon HD 7790 will be quite a bit (approximately 29%) better at anti-aliasing than the Radeon HD 3870 1GB, and able to handle higher screen resolutions while still performing well. (explain)

Radeon HD 7790		16000 Mpixels/sec
Radeon HD 3870 1GB		12400 Mpixels/sec
	Difference: 3600 (29%)

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 information (measured in megabytes per second) that can be transferred across the external memory interface in one second. The number is worked out by multiplying the bus width by its memory clock speed. In the case of DDR type RAM, the result 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 AA, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly write to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of 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 is also dependant on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.