Hardware Suggestions for 200Mbit routing

[nonzenze]

Hi all, sorry to be a noob but I just moved in to a building with 200/200 service and I'm finding that most random embedded routers (even the fancy ones like the Asus RT-N56U) just aren't fast enough to keep up, comparing the speedtest.net results from behind NAT to without it, even with very light load.

What sort of hardware should I look for? I'm not going to be doing any serious VPN or anything like that, just basic routing and some streaming/downloading. A lot of the LGA1155 MiniITX boards look very tempting but few have dual compatible NICs and the fact that most dual-port PCIE Intel cards are $150 (!!!) is very prohibitive. A few considerations:

(1) Smaller is better, but I'm not keen to spend a whole lot more money on it. MicroATX is fine, MiniITX is better.
(2) Quiet is essential, no 40mm fans please.
(3) Power is expensive here (.20-.25$/KWH), so buying an old P4 3GHZ off Craigslist is a non-starter. 50W is a good target since that's $7/mo in power. Any more and it becomes profitable to go for more expensive low-power hardware.
(4) Performance should be very close to un-NATed in the 200/200 range, even with a few hundred open connections. I was thinking i3 2100T for this, although I'd be open to other suggestions.
(5) $200-300 price target.

Here are some random things I looked at to pair with the i3 2100T:

(A) http://www.newegg.com/Product/Product.aspx?Item=N82E16813500069

PRO: Performance, form factor, 802.11N WiFi included
CON: NICs are 8111E and I'd rather not muck about compiling drivers

(B) http://www.newegg.com/Product/Product.aspx?Item=N82E16813138327
http://www.newegg.com/Product/Product.aspx?Item=N82E16833106015

PRO: NICs compatible
CON: Price is beyond range.

Any thoughts? I admit that maybe I'm shooting too high for 200/200 in a 50W power envelope, at least considering I don't want to pay more than $300 all-in. I can maybe relax that power requirement a bit, although each 10W increment is like $1.50/month. I could go with a dual core Atom and sacrifice some performance but I'm not sure if that would save me any power or money.

….

This is vexing!

[stephenw10]

50W seems completely reasonable to me for a 200Mbps connection.
Do you need to use new hardware?
My own Pentium-M based system draws less than 50W and is good for 400Mbps+.

Steve