GeForce GTX 980M vs Radeon HD 4890 2GB

Intro

Compare that to the Radeon HD 4890 2GB, which uses a 55 nm design. AMD has set the core frequency at 1000 MHz. The GDDR5 RAM works at a speed of 975 MHz on this particular card. 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 980M		100 Watts
Radeon HD 4890 2GB		190 Watts
	Difference: 90 Watts (90%)

Memory Bandwidth

The GeForce GTX 980M, in theory, should perform just a bit faster than the Radeon HD 4890 2GB overall. (explain)

GeForce GTX 980M		128000 MB/sec
Radeon HD 4890 2GB		124800 MB/sec
	Difference: 3200 (3%)

Texel Rate

The GeForce GTX 980M will be quite a bit (approximately 149%) more effective at anisotropic filtering than the Radeon HD 4890 2GB. (explain)

GeForce GTX 980M		99648 Mtexels/sec
Radeon HD 4890 2GB		40000 Mtexels/sec
	Difference: 59648 (149%)

Pixel Rate

If using high levels of AA is important to you, then the GeForce GTX 980M is the winner, and very much so. (explain)

GeForce GTX 980M		66432 Mpixels/sec
Radeon HD 4890 2GB		16000 Mpixels/sec
	Difference: 50432 (315%)

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 largest amount of information (in units of MB per second) that can be transferred across the external memory interface in a second. The number is worked out by multiplying the interface width by its memory clock speed. If the card has DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better 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 can be applied per second. This figure is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The higher this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of ROPs by the the card's clock speed. 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.