This is a bit ambiguous, as having 1000BASE-T ports does not necessarily imply being able to route up to full wirespeed - and AR9344, as in the RB2011, cannot - not at all (~150 MBit/s max).
No.
You have basically given yourself the answer here already, x86_64 is an options - especially if you want to achieve 1 GBit/s line speed (and other high performance features, e.g. SQM, VPN).
Devices like these (the later ones in that thread, not the AMD jaguar based ones) might come in handy.