Is the arduino too slow to read a high resolution pulse encoder?

Hi I just puled apart a printer and remover the motors with the encoders, my problem is than if i move the motor one time around
at different speeds the faster speed produces less pulses (missing some dew to the resolution at a given speed )
what Im trying to find is an CI that can operate fast enough to read each pulse and then read via an I2C protocol or similar
the only thing i can find are real-time counters and this here:
http://forum.arduino.cc/index.php?topic=52941.0

have you tried interrupts?

see - attachInterrupts on the tutorial page, can read up to 200 000's pulses a second without problem in software.

that did the trick! I still miss on avg +-3 pulses but that is hardware im working with thx a ton! for anyone other arduino noobs who is reading here a link http://arduino.cc/en/Reference/AttachInterrupt its sad i only have 2 pins to work with...

Can you post your code, as those 3 missing pulse can be captured too I think.

interrupts can be done on any pin - check this thread - PinChangeInt library- To attach interrupts to multiple Arduino (Uno/Mega) pins - Exhibition / Gallery - Arduino Forum -
It is a bit more complicated as there is one interrupt for all pins, and yo have to figure out in SW which pin it was. But that is what this lib is all about. I recall we optimized it quite well for speed.