Compare any two graphics cards:
GeForce GT 640 DDR3 vs GeForce GTX 650
IntroThe GeForce GT 640 DDR3 uses a 28 nm design. nVidia has set the core speed at 900 MHz. The DDR3 RAM is set to run at a speed of 1782 MHz on this particular model. It features 384 SPUs as well as 32 Texture Address Units and 16 Rasterization Operator Units.
Compare all of that to the GeForce GTX 650, which has a core clock speed of 1058 MHz and a GDDR5 memory speed of 1250 MHz. It also features a 128-bit memory bus, and makes use of a 28 nm design. It is made up of 384 SPUs, 32 TAUs, and 16 Raster Operation Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the GeForce GTX 650 should perform a lot faster than the GeForce GT 640 DDR3 overall. (explain)
Texel RateThe GeForce GTX 650 will be just a bit (about 18%) faster with regards to anisotropic filtering than the GeForce GT 640 DDR3. (explain)
Pixel RateIf using high levels of AA is important to you, then the GeForce GTX 650 is a better choice, though only just barely. (explain)
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 ComparisonPlease note that the price comparisons are based on search keywords, and might not be the exact same card listed on this page. We have no control over the accuracy of their search results.
Memory Bandwidth: Memory bandwidth is the max amount of data (measured in MB per second) that can be transported over the external memory interface in a second. It is worked out by multiplying the card's interface width by its memory speed. If it uses 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 AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed in one second. This number 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 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 most pixels that the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.