GeForce GT 640 DDR3 vs GeForce GTX 280

Intro

Compare those specs to the GeForce GTX 280, which features GPU core speed of 602 MHz, and 1024 MB of GDDR3 memory set to run at 1107 MHz through a 512-bit bus. It also features 240 SPUs, 80 TAUs, and 32 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
GeForce GTX 280		236 Watts
	Difference: 171 Watts (263%)

Memory Bandwidth

Theoretically speaking, the GeForce GTX 280 should be much faster than the GeForce GT 640 DDR3 in general. (explain)

GeForce GTX 280		141696 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 84672 (148%)

Texel Rate

The GeForce GTX 280 should be a lot (about 67%) more effective at texture filtering than the GeForce GT 640 DDR3. (explain)

GeForce GTX 280		48160 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 19360 (67%)

Pixel Rate

If using a high resolution is important to you, then the GeForce GTX 280 is superior to the GeForce GT 640 DDR3, and very much so. (explain)

GeForce GTX 280		19264 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 4864 (34%)

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 transferred past the external memory interface within a second. The number is calculated by multiplying the interface width by the speed of its memory. If the card has DDR type RAM, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This 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 graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.