GeForce GTX 650 vs Radeon HD 4890 2GB

Intro

Compare all of that to the Radeon HD 4890 2GB, which comes with clock speeds of 1000 MHz on the GPU, and 975 MHz on the 2048 MB of GDDR5 memory. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 ROPs.

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

Theoretically, the Radeon HD 4890 2GB should be a lot faster than the GeForce GTX 650 overall. (explain)

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

Texel Rate

The Radeon HD 4890 2GB is just a bit (about 18%) better at texture filtering than the GeForce GTX 650. (explain)

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

Pixel Rate

The GeForce GTX 650 should be a bit (about 6%) faster with regards to AA than the Radeon HD 4890 2GB, and also will be capable of handling higher resolutions without losing too much performance. (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 information (in units of MB per second) that can be transferred over the external memory interface within a second. It's worked out by multiplying the card's bus width by its memory clock speed. If the card has DDR memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better 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 texture map elements (texels) that can be applied in one second. This number is worked out by multiplying the total number of texture units by the core speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly record to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.