OK, that is going to almost certainly be Delayed ACK and / or LRO.  Also, should check that MPIO is set to Round Robin with IOs per path at 3.  (Default for RR, 1000 IOs before switching paths)  This link has a PDF which covers all the best practices for EQL + ESX.   There are some very important settings for performance and redudancy in this guide.  en.community.dell.com/.../20434601.aspx The boot up issue is likely different from the latency issue.  Since very little IO to the SAN occurs during startup.   If you watch the EQL GUI,  you can see how quickly the logins occurr. 
Hi,  I got a Dell PS4100xv with three (3) servers attached via 2x PC6224. The total IOPs consumption does not exceed 600 IOPs. Most of the time IOPs is around 300 IOPs. Looking at SAN HQ, the max IOPs supported by the array at RAID 6 should be around 1500 ms.   Latency is around 20 to 50 ms.   However it peeks around 80 to 100 ms. But this is not sustained.   What is acceptable latency for the EQL ? I have Windows 2008 R2 SP1 and some Linux VMs.   Application performance is acceptable.   Thanks, Paul
Acceptable Dell EQL PS4100xv Latency