A couple things. 

• The SB6190 is a docsis 3.0 device. Its not 3.1. Most ISP’s won’t support even gigabit speeds on docsis 3.0 devices even if they’re capable. (a few do but they’re rare). So without knowing your ISP, its challenging. But again, doubtful the ISP will support more than probably 800mbps from it. 
• the SB6190 only has gigabit ports. So even if the modem side supports faster speeds, the modem can only output up to gigabit speeds.  

Basically it comes down to the max potential speed you could get from that modem is gigabit. But even if it can put out gigabit, its uncertain if your isp will support those speeds on it. 

Thanks pelmans. I totally understand what you mean. My current xfinity plan is  400Mbps but at some point, I would probably upgrade to 1Gbps and thought this modem would support up to 1.4. However, the unit I purchased yesterday states up to 1Gbps, but all other reviews and boxes show that it can support up to 1.4 and I was not sure if there are different revisions of SN6190 or if Arris just changes the packaging and rebranded the modem. 

More than likely just rebranding. If you’re on xfinity, I’d actually return it for a docsis 3.1 device. Xfinity and cox have both been pushing at least docsis 3.1 devices by dropping the speed tiers for docsis 3.0 devices. 

I think the maximum xfinity supports is 800mbps on docsis 3.0 devices. And I think cox has required 3.1 for speeds higher than that 250-400mbps. (on newer accounts)  So if you’re planning on upping your speeds, I’d look at a faster modem. if you’re fine where you’re at, you should be good for a while. 

Go with S33 that has 2.5 Gbps Ethernet port for Internet plan 1.4 Gbps.  Your router Internet port also need to be greater than 1 Gbps to achieve up to 1.4 Gbps speed.

The packaging usually advertise the capable speed.  Since SB6190 support 32 downstream channel, it can support up to 1.4 Gbps download speed if your service provider will allow it.  Manufacture started to advertise the best internet speed.     

If you’re not currently paying for >1 gig, I wouldn’t worry about going to a better modem. Docsis 3.1 devices have been coming down in prices and with ISP’s starting to work on/rollout docsis 4.0 devices, expect them to get even lower and be more common. So if you haven’t upgraded yet to greater than 1 gig, I’d hold off on buying a new modem and just keep using the sb6190 (if its working fine). 

Plus on xfinity, the sb6190 will go up to 800mbps. That's all xfinity rates it for. It might hit a bit faster than that as xfinity over-provisions.