GeForce GT 640 DDR3 vs Radeon HD 4730

Intro

Compare all of that to the Radeon HD 4730, which comes with core speeds of 700 MHz on the GPU, and 900 MHz on the 512 MB of GDDR5 RAM. It features 640(128x5) SPUs along with 32 TAUs and 8 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 4730		140 Watts
	Difference: 75 Watts (115%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4730 should be 1% faster than the GeForce GT 640 DDR3 in general, because of its greater data rate. (explain)

Radeon HD 4730		57600 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 576 (1%)

Texel Rate

The GeForce GT 640 DDR3 should be much (approximately 29%) better at AF than the Radeon HD 4730. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
Radeon HD 4730		22400 Mtexels/sec
	Difference: 6400 (29%)

Pixel Rate

If running with high levels of AA is important to you, then the GeForce GT 640 DDR3 is a better choice, and very much so. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
Radeon HD 4730		5600 Mpixels/sec
	Difference: 8800 (157%)

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 transported across the external memory interface within a second. The number is calculated by multiplying the bus width by the speed of its memory. If it uses DDR type memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly write to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.