How to solve the VM's start storm in Hyper-V!

Hi guys:

I got a  problem . When I start the 40 VMs at the same time , the server almost  dead , after 35 minutes, all VMs start success.

There are my server hardware info:

1,CPU :  2  *   (Intel（R） Xeon（R）CPU    E5620 @ 2.40GHz  ) Core 4  , sum up 8 cores

2,RAM: 64 G

3, HDD: SAS * 4   ,disk speed 15000 ,  Raid 5 , IOPs 600 totally.

And i know 1 VM's start need 300 IOPs ,so when i start 40 VMs ,the start stormhappened.

So i want to know ,is there some way or solution to solve this problem.

Thank u guys very much!!!!