GeForce 9500 GT 512MB GDDR3 vs GeForce GT 640 DDR3

Intro

Compare all that to the GeForce GT 640 DDR3, which makes use of a 28 nm design. nVidia has clocked the core frequency at 900 MHz. The DDR3 memory is set to run at a speed of 1782 MHz on this specific card. It features 384 SPUs as well as 32 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 9500 GT 512MB GDDR3		50 Watts
GeForce GT 640 DDR3		65 Watts
	Difference: 15 Watts (30%)

Memory Bandwidth

As far as performance goes, the GeForce GT 640 DDR3 should in theory be much superior to the GeForce 9500 GT 512MB GDDR3 overall. (explain)

GeForce GT 640 DDR3		57024 MB/sec
GeForce 9500 GT 512MB GDDR3		25600 MB/sec
	Difference: 31424 (123%)

Texel Rate

The GeForce GT 640 DDR3 should be a lot (more or less 227%) more effective at AF than the GeForce 9500 GT 512MB GDDR3. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce 9500 GT 512MB GDDR3		8800 Mtexels/sec
	Difference: 20000 (227%)

Pixel Rate

The GeForce GT 640 DDR3 is a lot (approximately 227%) better at full screen anti-aliasing than the GeForce 9500 GT 512MB GDDR3, and also should be able to handle higher resolutions better. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce 9500 GT 512MB GDDR3		4400 Mpixels/sec
	Difference: 10000 (227%)

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 maximum amount of information (measured in MB per second) that can be transferred across the external memory interface in a second. It's worked out by multiplying the card's interface width by its memory clock speed. If the card has DDR type RAM, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. 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 number of texture map elements (texels) that can be applied in one second. This figure is worked out by multiplying the total number of texture units by the core speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly write to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.