Precision refers to the number of bytes used to represent numbers. Single precision numbers use 32 bits whereas double precision numbers use 64 bits. More bits allows larger numbers to be represented but operations (addition, subtraction, multiplication, division, etc.) on double precision numbers are slower than operations on single precision numbers. In other words it takes more time to add 2 double precision numbers than it does to add 2 single precision numbers.

Ok, understood, and seams logical! ;o)

Some GPUs have far more CUDAs with which to perform double precision calculations and they can do more double precision calculations per second than a GPU with fewer CUDAs. Your GTX 650 has relatively few CUDAS so it is relatively slow when a task has many millions of double precision calculations.

In fact, you're right about my GTX, it have 384 Cuda Cores! It appears to be a great number, but, after a few searches, now I know that is not so much. For example, the graphic card I wish to own next (in a few months, maybe for next xmas) contains 1152 Cuda cores, in my words : "C'est genre 3 fois plus trop plus mieux!"*

In my previous post I was theorizing that perhaps your card's double precision power is so small that it cannot keep up with Asteroids tasks and the demands of the display and that the WDDM portion of Windows thinks it's so slow the driver has crashed. That's just a theory, it might not be correct.

Thank you so much, for the very good explanations you gave me, and for the time you spent to write it down here. I don't know if you're right or not, but it makes sense, and all about the Cuda 32/64bits tasks is more clear to me now. ;)

* Trying to translate "my words" myself, I also ask google to do the same .....
Google result : It's kind 3 times more better too! (Pragmatic, Predictable, Synthetic, I don't like it.)
My way : It's kind 3 times more too much of more better! (Yeah, that's my words, smily, inflated & fun!)

P.S.: Minecraft and Boinc at the same time ;) A larger (and readable) copy of this picture is available here!

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Samy : from "Pays de Loire" : N47.586147,E1.336013
CPU: i5-3470S @2.9GHz / MB: GA-H77N-Wifi / GPU: GV-N650OC w 2GB @5GHz / RAM: 16GB @1600MHz
All that gives me entertainments, movies, music, games, and more, it helps, making me smile

Thank you so much, for the very good explanations you gave me, and for the time you spent to write it down here. I don't know if you're right or not, but it makes sense, and all about the Cuda 32/64bits tasks is more clear to me now. ;)

You're welcome and if I am not correct then someone will correct me or add to my explanation if it is not complete.

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