GeForce 9400 GT 256MB vs Radeon HD 4650 512MB

Intro

Compare that to the Radeon HD 4650 512MB, which features GPU core speed of 600 MHz, and 512 MB of DDR2 memory running at 500 MHz through a 128-bit bus. It also is comprised of 320(64x5) Stream Processors, 32 Texture Address Units, and 8 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 9400 GT 256MB		50 Watts
Radeon HD 4650 512MB		55 Watts
	Difference: 5 Watts (10%)

Memory Bandwidth

Performance-wise, the Radeon HD 4650 512MB should in theory be much superior to the GeForce 9400 GT 256MB overall. (explain)

Radeon HD 4650 512MB		16000 MB/sec
GeForce 9400 GT 256MB		12800 MB/sec
	Difference: 3200 (25%)

Texel Rate

The Radeon HD 4650 512MB should be quite a bit (approximately 336%) better at anisotropic filtering than the GeForce 9400 GT 256MB. (explain)

Radeon HD 4650 512MB		19200 Mtexels/sec
GeForce 9400 GT 256MB		4400 Mtexels/sec
	Difference: 14800 (336%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 4650 512MB is a better choice, by a large margin. (explain)

Radeon HD 4650 512MB		4800 Mpixels/sec
GeForce 9400 GT 256MB		2200 Mpixels/sec
	Difference: 2600 (118%)

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 max amount of data (measured in MB per second) that can be transported past the external memory interface within a second. It is calculated by multiplying the card's bus width by its memory clock speed. If it uses DDR type memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, 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 amount of texture map elements (texels) that are processed per second. This number is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher this number, the better the video 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 most pixels the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of ROPs by the the core speed of the card. 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 lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.