Poor wifi speeds

Since you are getting 100+ wired, that eliminates the cable line and DPC3010 from the problem.  It is definitely a WiFi issue.  The Netgear C3000 is a gateway, I assume you removed the DPC3010 before connecting it, you can't connect a gateway to a modem.  The X2000 has a dsl modem built-in.  They both are wireless N300 devices and not really suitable.  The AirPort Extreme is the only unit I would test with.

What are the WiFi specs on the device you are using to run speedtests?  Are you connecting using wireless g or n?  2.4GHz or 5GHz?  If you are using 2.4GHz, there could be a lot if interference killing your speed.  In the real world (forget specs) wireless g will give you about 20Mbps, wireless n about 40-50Mbps.  If you use the 40MHz channel setting on wireless n, you may push it 70-80Mbps it you get a clean signal with minimal interference.

If you really want to get 100+ Mbps, you need a client device capable of 5GHz wireless ac, your AirPort Extreme should handle that.

Ok, and yes 2.4 GHz "g" the only way to get anything close to the suggested speed is to get a AC class router? but also wouldn't you need a wireless card upgrade? We live in a two story townhouse and have the router on top of a entertainment center and an extender on the second floor. HMMMM looks like I will be looking for a wireless router upgrade. OH and the netgear C3000 was used before the cisco DOCSIS. :)

fharden, your current config is a Cisco DPC3010 modem into an AirPort Extreme, correct?  What generation AirPort Extreme do you have?  The original generation (2003) only supported "g", the 1st gen (2007) started supporting wireless n but not gigabit ethernet.  2nd gen (mid 2007) and up support both gigabit ethernet and wireless n.  The 6th gen (2013) added wireless ac.

Wireless g won't do any better than what you are getting.  Wireless n may double or triple your WiFi speed.  Wireless ac will make it hum ... possibly better than 150Mbps.

Yes, you need a card capable of whatever wireless standard you are using with your router.  So, yes, you will need a router upgrade if you have an older generation of the AirPort and a card upgrade.  You may also need to upgrade your extender if it doesn't support you new WiFi network.  If you are upgrading your router, I would look at the Netgear Nighthawk series.  They have the strongest radio of any WiFi router I've seen, no promises but may let you get away without the extender.

Thanks, AllenP! I was thinking I would need an upgrade. The airport is an older model, I guess it is time to retire it and get a nighthawk. Thank you guys for the help. FH