CM600 lost speed after replacing decrepit old ubee modem ?? spectrum internet

Hi folks--thanks for the responses--I think you are correct--puzzled me about the other modem being faster until the channel issue was explained.   The extra channels were actually hurting the performance based on y'alls prior reply.  I'm going to take the wires apart at the box and give them a good clean and put some "magic in a bottle" on them (contact enhancer) and see if that helps.  I suspect I will be getting Spectrum out here.   When this setup was originally installed,  the Spectrum guy had the wire hanging so low you could reach up and grab it.   I called several times and no one would come fix it,  so I got my come-along out and ratcheted the cable up myself and secured it.   Probably didn't help any, although I was putting the pressure on the "guide wire" part of the cable.   I'll post an update when I clean the cable ends--Thanks much!