Is there any notable difference in performance or price between the two?
Resonators can be cheaper but aren't used much anymore. Crystals will be much more precise than resonators.
is it possible to replace the crystal on our 2k9's with something faster?
I'v always used resonators in external circuits personally and found them to work fine.
is it possible to replace the crystal on our 2k9's with something faster?
Practically, no. The arduino-specific code is written for 16MHz and 8MHz only.
Resonators tend to be cheaper, in part because they have built-in capacitors (component count goes from 3 to 1). As already noted resonators are less precise, and crystals tend to have wider operating temperature ranges.
-j
I like resonators (fewer parts, easier PCB layout), but the often-quoted "they're cheaper" seems to be pretty "theoretical." In practice, there are large numbers of 16MHz crystals on the "sort-of-surplus" market (eBay, Allectronics, goldmine, etc) that go for prices lower than you can find for 16MHz ceramic resonators.
OTOH, the often-quoted superior accuracy of crystals assumes that someone looked carefully at the crystal specifications and oscillator specifications, and carefully picked capacitor values to match everything, which is ALSO rather "theoretical" if you're buying a random crystal from a random vendor and throwing on those 22pF caps from the official schematic. (and I'm not sure that the official design/partslist did that analysis either.)
Either crystal or resonator is very likely to be "good enough for most practical purposes, except clocks."
Right. Resonator is pretty much OK unless you need to be dead on with timing... like say for... I don't know... an ALARM CLOCK?
Crystals "tend" to come with a higher price tag and the need for 2 other capacitors, as already mentioned... I'd like to add that they are also more delicate. Drop one... or subject your design to a lot of shock and there's a chance you have an ex-crystal.
Audiophile "doityourselfers" will spend 100 times the cost of a part because they convince themselves they have a better results in the end. If you feel the need for more accurate timing... by all means get a crystal but then it's up to you to determine if you spent your cash wisely. I mean, do you have a way to measure the accuracy between either choice?
If you have some 16MHZ crystals you rescued from Junk Parts, by all means go for it.
I think what we are saying here is... resonators work... and they require fewer total parts. Simple is good.
pw
The need for crystal capacitors depends upon their load capacitance. Some of the newer 8pF crystals don't need any caps at all as capacitance of the clock pins is enough!
Don't forget to get some audiophile diodes while you're at it, for "much cleaner highs, increased resolution, more palpable mids, and tighter bass"!