GeForce GT 420 vs Radeon R9 390 8G

Intro

Compare all of that to the Radeon R9 390 8G, which features GPU core speed of 1000 MHz, and 8192 MB of GDDR5 memory set to run at 1500 MHz through a 512-bit bus. It also is comprised of 2560 SPUs, 160 TAUs, and 64 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
Radeon R9 390 8G		275 Watts
	Difference: 225 Watts (450%)

Memory Bandwidth

Theoretically speaking, the Radeon R9 390 8G should be 1233% quicker than the GeForce GT 420 overall, due to its higher bandwidth. (explain)

Radeon R9 390 8G		384000 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 355200 (1233%)

Texel Rate

The Radeon R9 390 8G should be much (about 2757%) better at anisotropic filtering than the GeForce GT 420. (explain)

Radeon R9 390 8G		160000 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 154400 (2757%)

Pixel Rate

The Radeon R9 390 8G will be a lot (approximately 2186%) more effective at anti-aliasing than the GeForce GT 420, and should be capable of handling higher resolutions without losing too much performance. (explain)

Radeon R9 390 8G		64000 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 61200 (2186%)

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: Bandwidth is the maximum amount of information (measured in megabytes per second) that can be transported over the external memory interface in one second. The number is calculated by multiplying the interface width by its memory speed. If it uses DDR type memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This figure is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the video 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 amount of pixels the graphics card could possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs 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 is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.