I be one of the first to get a Motorola SB6120 -- and be very much satisfied with the ease of set-up , the awesome speed , the functionality , and the workmanship . but , like all electronic gizmo , they tend to crap out after a few year . when my sb6120 start drop upstream channel , I look to Motorola once again -- right here at Amazon -- and find the new Motorola sb6121 . after check the spec , I find that the new sb6121 Model have the latest ipv6 technology -lrb- higher bandwidth capability -rrb- that be not available on the sb6120 . the newer ipv6 technology allow connection speed up to 160 mbp. , against the 150 mbp of the sb6120 . ipv6 be not in common usage yet , but it will be pretty soon -- and the sb6121 will be ready with the fastest speed available !! the new sb6121 be a super-easy set-up , and the connection speed be fast and steady . compare the DOCSIS 3 sb6120 to the newer sb6121 : 1 . - the sb6121 be smaller -lrb- height and depth be smaller , width be greater -rrb- . 2 . - the sb6121 run slightly -lrb- average about 5 degree f -rrb- warmer than the sb6120 . 3 . - connection speed , latency , and jitter be better with the sb6121 than the sb6120 -- and WAY faster than ANY DOCSIS 2 modem , regardless of manufacturer . some tip I learn from use the Motorola DOCSIS 3 modem with 2 different -lrb- d-link dir-655 and Netgear wnr3500l -rrb- `` n '' - speed Wireless Routers : the sb6120 run coolest when mount to a wall or other vertical surface , and space approximately 1\/2-inch away from the surface . this allow a adequate air flow that be necessary to keep the Modem cool . mount with the wire point straight down , the sb6120 run at about 95 degree f in a 78 degree room when mount away from a wall . temperature measure with Mastercool Infra-Red Laser Thermocouple gun -lrb- available at Amazon -rrb- . the new sb6121 be smaller than the sb 6120 , and it run a little bit warmer -lrb- 98-100 f -rrb- , even when mount the same way as the sb6120 . I suggest that you mount the new sb6121 1\/2 '' away from the wall as well , but with the wire point straight back . whatever you do , DO not stack anything on ANY Modem or Router !! both of these device give off heat and electrical interference , and will perform they best when space about 4 foot apart , which keep the interference from overlap and kill the Wireless Router 's range . when you get you internet connection go , go to the Motorola Modem 's Home Page : sample snapshot of my sb6121 = Cable Modem Status Signal address Configuration Logs Open Source help this page provide information about the current upstream and downstream signal status of you Cable Modem . -------------------------------------------------------------------------------- downstream Bonding Channel Value Channel ID 49 50 57 58 frequency 837000000 hz 843000000 hz 861000000 hz 867000000 hz signal to Noise Ratio 37 db 37 db 38 db 38 db downstream modulation qam256 qam256 qam256 QAM256 Power LevelThe downstream power level reading be a snapshot take at the time this page be request . please reload\/refresh this Page for a new reading -1 dbmv -1 dbmv -1 dbmv -1 dbmv Upstream Bonding Channel Value Channel ID 3 1 2 frequency 36100000 hz 23300000 hz 29600000 Hz Ranging Service ID 7425 7425 7425 Symbol Rate 5.120 Msym\/sec 2.560 Msym\/sec 5.120 Msym\/sec Power Level 45 dbmv 45 dbmv 45 dbmv Upstream modulation -lrb- 3 -rrb- qpsk -lrb- 3 -rrb- 64qam -lrb- 3 -rrb- qpsk -lrb- 2 -rrb- 16qam -lrb- 3 -rrb- 64qam -lrb- 3 -rrb- qpsk -lrb- 3 -rrb- 64QAM Ranging Status Success Success Success Signal stats -lrb- codeword -rrb- Bonding Channel Value Channel ID 49 50 57 58 total unerrored codeword 1457238562 1457238645 1457237949 1457238150 total correctable codeword 17 26 23 27 total uncorrectable codeword 1031 937 1682 1468 -------------------------------------------------------------------------------- Status | Signal | address | Configuration | Logs | Open Source | help  copyright 1997-2008 it should give a snapshot of the spec for your modem . you will be look for 4 downstream channel that read SNR @ 37-38 db and the power level at around 0 dbmv . upstream power level on all 3 bonding channel should read around 45-50 dbmv . a deviation of 5 from any of these figure indicate a problem . if the Modem 's signal be solid and constant , but the power level reading be 5 point off in either direction , check you outdoor splitter or tap first , because they tend to crap out when they be expose to heat for long period . the operating temperature for splitter and tap be only 140 degree F. maximum , and that temperature be easily reach in direct sunlight , even when enclose . those of you who live in hot climate may notice that the Modem 's downstream power level drop off 1 or 2 point when the outside temp get up to 110 f or higher . do not panic !! in case of rapture , dial 1-800-oh Jesus . ; -rrb- -rrb- I find the rca dh24sp high-bandwidth -lrb- 5-2400mhz -rrb- 2-way signal splitter -lrb- available at Amazon -rrb- to be a excellent handler of the high-speed signal of Cable , Satellite , and hdtv signal . it be a `` 2-way '' splitter , so the power flow equally in either direction , enable MUCH higher upload speed . if you need a tap for unequal cable length , a CommScope SV-DC-6G Digital tap work well for I . for strong and clear Wireless range and reception , use only Category 6 -lrb- shield -rrb- ethernet cable -lrb- available at Amazon -rrb- between you Modem and Router , and between you router and Main computer . good Luck !!