c9429b30_yper_V_VS_Citrix_Xen___My_Blog__Hypervisor_Attributes
[VMware ESXi 5.0] Ability to reclaim unused memory, de-duplicate memory pages, compress memory pages Only uses ballooning. No ability to de-duplicate or compress pages. [Citrix XenServer 5.6 FP1] Only uses ballooning.No ability to de-duplicate or compress pages. Does not adjust memory allocation based on VM usage. [Hypervisor Attributes] 
Advanced Memory Management
Comparison between Vmware VS Hyper-V VS Citrix Xen | My Blog
Hypervisor Attributes