GeForce GT 640 DDR3 vs GeForce GTS 450

Intro

Compare those specifications to the GeForce GTS 450, which uses a 40 nm design. nVidia has clocked the core frequency at 783 MHz. The GDDR5 memory runs at a frequency of 902 MHz on this model. It features 192 SPUs as well as 32 TAUs and 16 Rasterization Operator 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 GT 640 DDR3		1560 points
GeForce GTS 450		1453 points
	Difference: 107 (7%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
GeForce GTS 450		106 Watts
	Difference: 41 Watts (63%)

Memory Bandwidth

Theoretically, the GeForce GTS 450 should perform just a bit faster than the GeForce GT 640 DDR3 in general. (explain)

GeForce GTS 450		57728 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 704 (1%)

Texel Rate

The GeForce GT 640 DDR3 is a little bit (about 15%) faster with regards to texture filtering than the GeForce GTS 450. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce GTS 450		25056 Mtexels/sec
	Difference: 3744 (15%)

Pixel Rate

The GeForce GT 640 DDR3 will be a little bit (approximately 15%) more effective at full screen anti-aliasing than the GeForce GTS 450, and able to handle higher resolutions while still performing well. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce GTS 450		12528 Mpixels/sec
	Difference: 1872 (15%)

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 data (counted in megabytes per second) that can be transported over the external memory interface in one second. It is worked out by multiplying the bus width by the speed of its memory. If the card has DDR type memory, the result should be multiplied by 2 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 AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This number is calculated by multiplying the total texture units of the card by the core speed of the chip. The better this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.