My system is very similar.

Same processor, amount/speed of ram.
Same video card, although mine is in the process of dying.
I have an SSD, mine is close to 200mb/sec sequential reads, not sure how that compares to Owl's.

The game is playable in Stormwind, even primetime/weekends on a very high population server (Cenarius-US is higher population than any of the servers with massive numbers of boxers).
Epic 310 flying does not break in SW/peak times, although Grid shows the toons far enough back to not be in healing range.
With ground mounts, they never break follow in cities or battlegrounds.
No issues to prevent questing, instances, mass pvp, etc.