Citrix Provisioning – vDisk RAM cache size not able to set more than 4GB/8GB

I had an issue when trying to assign vDisk RAM cache for 10GB, In the target device RAM cache was showing only 8GB. I know it’s a limitation in Windows 2003 STD where the OS limitation is 4GB, however i had Windows 2003 enterprise edition.

Did some check and found there’s a regkey to be tweaked to set the value for more than 8GB.

  • Make the vDisk to Private RW mode
  • Navigate to 

HKLM\system\CurrentControlSet\Services\bnistack\Parameters\

  • If not already present, create DWORD “WcMaxRamCacheMB”.  Assign the required amount of vDisk cache in  MB. In my case i’ve assigned 14GB.

RAM cache_reg

  • Shutdown target device & make it Standard RW mode; Cache Type RAM and specify 14GB for the cache in vDisk properties.
  • Boot target devices, you will be able to see 14GB assigned for vDisk RAM cache.

RAM Cache

Hope this helps!