GeForce GTX 660 vs Radeon HD 4850 X2 1GB

Intro

Compare those specifications to the Radeon HD 4850 X2 1GB, which comes with GPU clock speed of 625 MHz, and 1024 MB of GDDR3 RAM set to run at 993 MHz through a 256-bit bus. It also is made up of 800(160x5) Stream Processors, 40 TAUs, and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 660		140 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 110 Watts (79%)

Memory Bandwidth

Theoretically speaking, the GeForce GTX 660 should be a bit faster than the Radeon HD 4850 X2 1GB overall. (explain)

GeForce GTX 660		144192 MB/sec
Radeon HD 4850 X2 1GB		127104 MB/sec
	Difference: 17088 (13%)

Texel Rate

The GeForce GTX 660 will be a lot (approximately 57%) more effective at AF than the Radeon HD 4850 X2 1GB. (explain)

GeForce GTX 660		78400 Mtexels/sec
Radeon HD 4850 X2 1GB		50000 Mtexels/sec
	Difference: 28400 (57%)

Pixel Rate

If using a high screen resolution is important to you, then the GeForce GTX 660 is superior to the Radeon HD 4850 X2 1GB, though only just barely. (explain)

GeForce GTX 660		23520 Mpixels/sec
Radeon HD 4850 X2 1GB		20000 Mpixels/sec
	Difference: 3520 (18%)

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: Memory bandwidth is the maximum amount of data (measured in MB per second) that can be moved across the external memory interface within a second. It's calculated by multiplying the interface width by the speed of its memory. If the card has DDR memory, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly write to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.