That is extremely surprising - there are not any fixes related to VMware performance in SP4 for anyone that has SP3 installed. The only VMware changes in SP4 are
A workaround for EMC ScaleIO (ScaleIO is a proprietary storage platform whose client software on ESX introduces fake FC HBAs whose WWNs are not very unique. In large VMware environments, one can have duplicative fake WWNs, which OCI's datasource used to detect and fail on). OCI now pretends these fake ScaleIO HBAs do not exist.
And a minor supportability improvement where we are logging the vSphere build number so we can quickly understand against which vSphere release+update a given datasource is talking to.
We do not support uninstalling Service Packs - if a Service Pack introduces a problem, we will need to fix it with a patch.