Radeon HD 3870 X2 1GB vs Radeon R9 390X 8G

Intro

Compare those specifications to the Radeon R9 390X 8G, which has GPU clock speed of 1050 MHz, and 8192 MB of GDDR5 memory set to run at 1500 MHz through a 512-bit bus. It also is comprised of 2816 SPUs, 176 TAUs, and 64 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

As far as performance goes, the Radeon R9 390X 8G should theoretically be a lot better than the Radeon HD 3870 X2 1GB overall. (explain)

Radeon R9 390X 8G		384000 MB/sec
Radeon HD 3870 X2 1GB		144128 MB/sec
	Difference: 239872 (166%)

Texel Rate

The Radeon R9 390X 8G should be quite a bit (approximately 600%) better at anisotropic filtering than the Radeon HD 3870 X2 1GB. (explain)

Radeon R9 390X 8G		184800 Mtexels/sec
Radeon HD 3870 X2 1GB		26400 Mtexels/sec
	Difference: 158400 (600%)

Pixel Rate

The Radeon R9 390X 8G is much (about 155%) faster with regards to FSAA than the Radeon HD 3870 X2 1GB, and also will be capable of handling higher screen resolutions better. (explain)

Radeon R9 390X 8G		67200 Mpixels/sec
Radeon HD 3870 X2 1GB		26400 Mpixels/sec
	Difference: 40800 (155%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the largest amount of data (counted in megabytes per second) that can be transported over the external memory interface within a second. It is worked out by multiplying the bus width by the speed of its memory. If the card has DDR type memory, it should be multiplied by 2 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 AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly record to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.