Sb6121 Internet speed drops every 1-2hrs

Just upgraded to The Sb6121 from sb5101. Never had a problem with it until I switch modem. The Sb6121 speeds would drop from 12mb to 0.5mb every 2hrs or so. I would have to reboot my modem in order for it to go back up to regular speed. Quite annoying and was thinking a I got a defective one. Here my signal get, also using a Linksys Wrt54g router

Channel ID1 4 5 7 Frequency561000000 Hz 579000000 Hz 585000000 Hz 597000000 Hz Signal to Noise Ratio37 dB 36 dB 37 dB 37 dB Downstream ModulationQAM256 QAM256 QAM256 QAM256 Power LevelThe Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading3 dBmV  2 dBmV  1 dBmV  1 dBmV  UpstreamBonding Channel ValueChannel ID14 13 15 Frequency30600000 Hz 25300000 Hz 37000000 Hz Ranging Service ID12687 12687 12687 Symbol Rate5.120 Msym/sec 2.560 Msym/sec 5.120 Msym/sec Power Level51 dBmV 50 dBmV 51 dBmV Upstream Modulation[3] QPSK[3] 64QAM [3] QPSK[3] 64QAM [3] QPSK[3] 64QAM Ranging StatusSuccess Success Success Signal Stats (Codewords)Bonding Channel ValueChannel ID1 4 5 7 Total Unerrored Codewords46819300 45868396 45868346 45867602 Total Correctable Codewords1190 1089 1310 1440 Total Uncorrectable Codewords2444 2447 2423 3199