Netgear FVS318v3 throughput issues

I recently installed a Netgear FVS318v3 router (with the latest firmware) and I seem to be having some considerable throughput issues with it. I have a 6mbs down/2mbs up cable connection to the WAN port of the router and repeated speed tests give me an average down speed of 1.2-1.5mbs? I did these tests with a PC connected directly to a LAN port on the router to avoid any possible bottlenecks in the network. However, when I connect a PC directly to the cable modem I get average speeds of 5.3-5.5 mbs down. Anyone have any ideas here?

Configuration is like this:

[code:1:c0060f1549][Cable Modem]
|
[FVS318v3 Firewall/Router]
|
[10/100 16 Port Switch]-[10/100 16 Port Switch]-[10/100 16 Port Switch]
| | |
[LAN] [LAN] [LAN][/code:1:c0060f1549]

The router is using NAT, I have to daisy chain the switches because if plug them directly into the router nothing will go through.

Yes, that is what i'm saying. However, when i connect each switch to its own separate port on the router, all of the activity lights for each port on the switches blink rapidly and the network becomes unusable.

i don't see why that would be a problem if the cable length works from switch to switch but not from the switch to a router?

All Ethernet networks that run Collision Detect (CD) have a minimum cable length to function properly because of reflections.

The minimum length defined for 100BaseT Ethernet networks is rarely an issue, since it is not the length of an individual wire that must meet the specification, but the length between nodes.

However, if overdriving is a problem, a longer cable might help.

Something is seriously amiss with your network. My guess is your router is screwed up. Logically, there is no difference between plugging your second switch into one of the 8 ports on the router vs plugging it into one of the ports on your first switch. The former is much preferred, since you want to minimize the daisy-chaining of switches to maximize network performance in general.

You need to be looking at why the other 7 ports on your router (or perhaps the internal Ethernet switch on your router) are not functioning correctly.