A General Question about the BBB

I would like an opinion please, on whether or not the BBB is suited to my intended project.
I need a fast processor that can read a 20 mega samples per second A/D (Maxim) every 100 nanoseconds.
This means I will probably have to execute (guessing here) 5 to 15 instructions within a 100ns window to capture and store the signal from the A/D.
Will the overhead of having a Linux operating system allow this kind of speed or, if not, can I bypass the OS and work
directly with the processor?
Is it overkill to use the BBB for this or is there something less complicated available that has the speed I need.
I really don’t need most of the other functions except the ability to program the software I write and use the display
driver for a graphical output.
My SBC background is with much slower, simpler processors like the Stamp series which are way too slow.
Thanks for any input on this!

20Msps every 100 nano seconds ? What have you been smoking ? I want some.

As 20 megasamples per second is a sample every 50 ns I am guessing you are going to need to execute in shorter time than 100 ns unless it is buffered. If the application doesn’t require processing the samples in real time, you could buffer the A/D converter into a FIFO and have the BBB empty the FIFO at intervals but I’m not convinced it would keep up. Is this a “bursty” application that runs only a few seconds at a time or is it expected to run continuously? This might be an application more suited to a dedicated CPU running a real-time OS or Linux on a multi-core platform with one core dedicated to your application.

George B, Thanks for the input. The converter is rated at speeds UP TO 20 MSPS. I will not need all of that speed as I intend to sample it every 100 ns.
Yes this is a situation where all I need to do is capture and store a reading from the A/D, wait until my 100 ns, has elapsed, capture & store next, etc.
After 30 iterations this loop will halt and the data will be processed later. So I really just need the speed to capture the data. Everything else can be done
So will the BBB be able to do this? I bought one already so I am in the game. It is the fastest popular board out there, or is it?

Looking at the bill of materials I see it has 4 oscillators on board: 32.768KHz, 25 MHz, 24 MHz and 24.576 MHz. How can this run at 1GHz ?
Is there a multiplier somewhere?

You're correct, the internal clock is generated by onboard PLL. There
aren't any 1GHz crystals---the highest I've seen is around 300 MHz.