I especially liked the AWS forum post being breathlessly circulated which is from someone claiming that their business critical workload no longer fits on a single m1.medium (1 vCPU, <4GB RAM), joined by someone else who was actually swapping and hitting the OOM killer.
There is a real impact but this is going to be the lazy IT worker's new plausible excuse of the day for months…
It matters not what the workload was running on before or accusations of laziness, the key takeaway from that post was that there was an impact on performance caused by the Meltdown/Spectre mitigations.
The fact another commenter barged into the thread with an unrelated issue simply shows that AWS forum operates within the Law of Forums (which states all threads are to be cross pollinated with unrelated issues from at least one other user).
EDIT: I should say that if this fellow is the only affected user from all the computer users of the world, then the mitigations applied can be called successful. That seems unlikely :-)
In this case, the thread made it clear that the real problem was that they didn't have a good deployment story — notice how the original poster was mentioning needing to move everything to an m3.medium manually? I would be quite surprised if they haven't had other problems in the past (e.g. what happens when a system update kicks off if that server is already running at 90+% utilization? or when they get more users and/or the existing users start doing slightly more) but hadn't wanted to deal with the hassle of migrating.
This.