GeForce GTX 650 vs Radeon HD 4850 X2 512MB

Intro

Compare all of that to the Radeon HD 4850 X2 512MB, which features a core clock speed of 625 MHz and a GDDR3 memory speed of 993 MHz. It also features a 256-bit memory bus, and uses a 55 nm design. It features 800(160x5) SPUs, 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 4850 X2 512MB		250 Watts
	Difference: 186 Watts (291%)

Memory Bandwidth

Performance-wise, the Radeon HD 4850 X2 512MB should in theory be much superior to the GeForce GTX 650 in general. (explain)

Radeon HD 4850 X2 512MB		127104 MB/sec
GeForce GTX 650		80000 MB/sec
	Difference: 47104 (59%)

Texel Rate

The Radeon HD 4850 X2 512MB will be much (more or less 48%) more effective at anisotropic filtering than the GeForce GTX 650. (explain)

Radeon HD 4850 X2 512MB		50000 Mtexels/sec
GeForce GTX 650		33856 Mtexels/sec
	Difference: 16144 (48%)

Pixel Rate

The Radeon HD 4850 X2 512MB will be a bit (about 18%) better at anti-aliasing than the GeForce GTX 650, and capable of handling higher screen resolutions better. (explain)

Radeon HD 4850 X2 512MB		20000 Mpixels/sec
GeForce GTX 650		16928 Mpixels/sec
	Difference: 3072 (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 (in units of MB per second) that can be transferred over the external memory interface in a second. It's worked out by multiplying the card's bus width by its memory speed. If the card has DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster 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 are processed in one second. This figure is worked out by multiplying the total texture units by the core clock speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.