Charter Internet Question

Yep .. you got screwed.  It is that simple.  

The 12Mbps is a max peak and there is no guarantee that you will get 12Mbps 24x7x365.  In fact, as you have seen the average real-world throughput is 8.6 Mbps.

Get your money back or have them reprovision things for no additional money so you get average of 12Mbps on spot-check throughput tests.

Some routers become the bottleneck and some cam be finicky about the exact structure of the packets.  What is the make and model of your router?

It's the standard SMC Networks that Charter installs. Model SMCD3GN2.  As a side note, I asked them to switch their router back to a static IP and let me use my router. It's just a cheap D Link. I was able to get 68.5 average over 10 desktops using that configuration. Would I be better off to look into something like a Cisco Gigabit Wireless router and change the Dell 10/100 switch out to a gigabit switch?

By the follow-up comments I misinterpreted what you were doing.  Are you saying both routers are hooked up to the same (new) WAN port supplied by Charter?    I interpreted this as you had both ISP's equipment in and was testing the Charter with their router as the gateway, using same back-end PCs, then comparing that to the AT&T + AT&T router before you killed the AT&T

If you simply did nothing more than reconfigured the AT&T router to use the gateway IP/settings so it could work on Charter then DaviMcCarn is right on.   You need to do some tuning.

Check things like MTU size, make sure full duplex, and look at event logs.  Bottleneck may also be firewall rules (they chew up CPU time so bottleneck may be CPU and not bandwidth).

Your benchmarking could also be hindered by the wrong DNS settings.  Make sure they are set to appropriate values.  Are/were you using a proxy server?

Since this is commercial, really do talk to Charter.  They have some great software and can certainly confirm whether the problem is between the internet and your WAN port, or your WAN / and local LAN ports.

No, I have both AT&T and Charter Modem / Routers. But I am not using both at the same time. I was just making the comparison as originally configured AT&T Modem / Router to my switch passes 97% of the advertised speed through to the end pc's. Charter only passed 8-9%.

I then asked Charter to let their modem act as a gateway into a cheap DLink router and was able to get up to 68% of the advertised speed to the end pc's.

So that leaves me wondering if I need to upgrade the router and switch to best take advantage of the available bandwidth. Charter is absolutely no help. Their tech just left the office. He said he could get 101.5Mbps out of their modem and it was up to me to configure the router / switch and other equipment.

Are any of the PC's connected directly to the Charter box?
Gigabit switches can be very finicky about their autonegotiation and maybe that Dell switch is connecting to it at 10Mbps.

No, Right now 1 Cat5 from Charter modem to router WAN port. 1 Cat5 from Router to 24 port Dell 10/100 switch that distributes traffic to 10 VOIP Phones, 10 PC's and 2 Dell Servers. I'm not sure that's the best configuration. I was considering using a POE switch for the VOIP and a separate switch for the LAN Printers and PC's.

Proposed-Network.pdf

Run one of the PC's directly to the Comcast box and rerun the speedtest.  If its suddenly much faster, replace the dell switch.  If it isn't, go scream at Comcast!

Connected Directly its 102Mbps. Did you take a look at the proposed schematic?

The caution I would inject is that; unless Charter's modem can be put into bridge mode and you have the IP's to put into the Cisco router, you'll have real problems with any inbound traffic because you will need to port forward both devices.
The Charter/SMC box has wireless.  Why not skip the Cisco, altogether?

If I let them route the traffic I'm only getting 8.6 through. Routing myself and their box acting only as a bridge, I can improve the throughput dramatically. As it is configured currently with the 2716 Dell Switch in unmanaged mode and the DLink Router set to static IP with default settings, the network is fast enough. I'm just having some call quality issues just like I had with the U-Verse (AT&T). I'm just trying to come up with a solution. I just don't know if that solution is a router in the 1000-2000 dollar range or if I can fix the problem with the less expensive Cisco components in the diagram I attached.