GeForce GT 640 DDR3 vs GeForce GTX 580

Intro

Compare those specifications to the GeForce GTX 580, which features a core clock speed of 772 MHz and a GDDR5 memory frequency of 1002 MHz. It also uses a 384-bit bus, and makes use of a 40 nm design. It features 512 SPUs, 64 TAUs, and 48 Raster Operation Units.

Display Graphs

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Benchmarks

These are real-world performance benchmarks that were submitted by Hardware Compare users. The scores seen here are the average of all benchmarks submitted for each respective test and hardware.

3DMark Fire Strike Graphics Score

GeForce GTX 580		4956 points
GeForce GT 640 DDR3		1560 points
	Difference: 3396 (218%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
GeForce GTX 580		244 Watts
	Difference: 179 Watts (275%)

Memory Bandwidth

In theory, the GeForce GTX 580 will be 237% faster than the GeForce GT 640 DDR3 overall, due to its higher data rate. (explain)

GeForce GTX 580		192384 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 135360 (237%)

Texel Rate

The GeForce GTX 580 will be much (about 72%) better at AF than the GeForce GT 640 DDR3. (explain)

GeForce GTX 580		49408 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 20608 (72%)

Pixel Rate

The GeForce GTX 580 is a lot (about 157%) more effective at anti-aliasing than the GeForce GT 640 DDR3, and will be capable of handling higher resolutions without slowing down too much. (explain)

GeForce GTX 580		37056 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 22656 (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: Bandwidth is the largest amount of data (in units of MB per second) that can be transported across the external memory interface in one second. It is calculated by multiplying the card's interface width by the speed of its memory. If the card has DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This figure is worked out by multiplying the total texture units by the core 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 a second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount 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 fill rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.