Is N600-WNDR3400v2 Router too old technology

> Model: WNDR3400v2|N600 Wireless Dual Band Router

   Firmware version?  Connected to what?

> [...] On wired connection to modem, [...]

   You mean some (unspecified) "modem", not your WNDR3400v2 ("Router")?

> [...] I get around 490 MB download speed. [...]

   You won't see that kind of speed, wired or wireless, through a router
whose Ethernet ports are limited to 100Mb/s.

   Visit http://netgear.com/support , put in your model number, and look
for Documentation.  Get the User Manual (at least).  Read.  Look for
"Ethernet" and "Technical Specifications".

> [...] as soon as I switch to wireless, speed drops to between 10-70
> MB.

   Mb/s?  ("B" = byte = 8 bits, "b" = bit.)

   "switch" _what_ "to wireless"?  Does your (unspecified) wireless
device get higher speeds on a different router?  Is your bottleneck your
WNDR3400v2, or your (unspecified) wireless device?

> [...] Is my router too old? [...]

   "too old" for what?  With its "Fast Ethernet" ports ("Fast" for 1999,
that is), it probably is "too old" for modern wireless devices or for
your 500Mb/s Internet service.

   Whether your (unspecified) wireless device will see a higher speed
from a faster router might depend on the properties of that device, as
well as the properties of the router.

> [...] If so any recomendations, please.

   Almost anything with gigabit/s Ethernet ports would have a better
chance of getting above 100Mb/s.  Something with "AC" wireless would
normally be faster than your current "N" wireless.

   What you should get to replace your antique would depend on your
actual requirements and constraints (budget, for example).