"Is the generally acceptable level of CRC errors on a device 1% or less"
There an old rule-of-thumb, that TCP, well at least for old bulk data transfers, considered an error rate of 1% or less, "acceptable"; don't recall such a rule for CRC errors, though. I.e. A CRC error rate of 1% might be considered very "high".
Actually, different media specs, I believe, have an "expected" bit error rates, like 1 bit error somewhere in the range of 10E12 to 10E20. Do note, that a single bit error will likely cause a CRC error (BTW, there's not 100% error detection; CRC algorithms have their own "quirks") for whatever group of bits the CRC is being applied to, like a Ethernet frame. (I also believe bigger blocks will raise the overall CRC error percentage, although I also recall "too large" blocks impact CRC error detection - the mathematics behind CRCs make my head hurt - laugh.)
If you can find the expected BER spec for your media, based on the number of bits per your averaged sized CRC "block" (e.g. frame/packet), you should be able to compute an expected CRC error count.
NB: Also BTW, there are different CRC algorithms, that are used for different media, to best detect bit errors on that media.
