GeForce GTX 650 vs Radeon HD 4890 2GB

Intro

Compare that to the Radeon HD 4890 2GB, which has GPU core speed of 1000 MHz, and 2048 MB of GDDR5 memory set to run at 975 MHz through a 256-bit bus. It also is made up of 800(160x5) SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 650		64 Watts
Radeon HD 4890 2GB		190 Watts
	Difference: 126 Watts (197%)

Memory Bandwidth

In theory, the Radeon HD 4890 2GB will be 56% faster than the GeForce GTX 650 overall, because of its higher data rate. (explain)

Radeon HD 4890 2GB		124800 MB/sec
GeForce GTX 650		80000 MB/sec
	Difference: 44800 (56%)

Texel Rate

The Radeon HD 4890 2GB will be a bit (about 18%) more effective at AF than the GeForce GTX 650. (explain)

Radeon HD 4890 2GB		40000 Mtexels/sec
GeForce GTX 650		33856 Mtexels/sec
	Difference: 6144 (18%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the GeForce GTX 650 is a better choice, not by a very large margin though. (explain)

GeForce GTX 650		16928 Mpixels/sec
Radeon HD 4890 2GB		16000 Mpixels/sec
	Difference: 928 (6%)

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 data (in units of megabytes per second) that can be moved across the external memory interface within a second. The number is worked out by multiplying the interface width by its memory speed. If it uses DDR type RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, 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 is calculated 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 number of pixels the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.