Here is the Post with the Difference between ESX 3.5 & ESX 4. I believe this would be the one of the definite questions in interview. Will working towards to bring the differences between all editions of ESX version.
If you looking for Difference between vSphere 4.1 and vSphere 5. Please refer my blogpost on “Difference between vSphere 4.1 and vSphere 5″
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Features | ESX 3.5 | ESX 4 |
Linked Mode | No Linked Mode Support | Linked Mode Supportis introduced in vSphere 4.0 |
Host Profiles | No Host Profiles | Host Profiles is Introduced in vSphere 4.0 |
Centralized License | Require dedicated License server | License can be managed within vCenter server |
Performance chart | Yes | Lot More enhancements |
Events and Alarms | Yes | Lot More enhancements |
Fault tolerance | Not Available | Available from vSphere 4.0 |
Storage VMotion | SVMotion available only with CLI | SVMotion available in GUI |
VMotion | Yes | Yes |
Virtual CPUs per host | 192 | 512 |
Virtual Machines per host | 170 | 320 |
Logical processors per host | 32 | 64 |
RAM per host | 256 GB | 1 TB |
Maximum Service console Memory | 800 MB | 800 MB |
DRS | Yes | Yes |
VMware Data Recovery | Backup using VCB (VMware Consolidated backup) | VMware Data Recovery and VCB support |
Enhanced VMotion Compatibility (EVC) | No EVC | EVC is introduced in vSphere 4.0 |
VMware HA Admission Control | Yes but without options to reserve failover capacity | Admission Control is improved to provide more flexible configuration options to reserve failover capacity. |
High Availability Clustering with Windows Server 2000, 2003, 2008 | Not Available | Available in vSphere 4.0 |
Serial Attached SCSI (SAS) | Not Available | Available to support MSCS on win 2008 |
Hosts per storage volume | 32 | 64 |
Fiber Channel paths to LUN | 32 | 16 |
NFS Datastores | 32 | 64 |
Hardware iSCSI initiators per host | 2 | 4 |
Virtual Machine Hot Add Support | NO | Yes |
Number of virtual CPUs per virtual machine | 4 | 8 |
Virtual Hardware version | 4 | 7 |
RAM per virtual machine | 64 GB | 255 GB |
virtual machine swap file Size | 65532MB | 255GB |
VMDirectPath for Virtual Machines | NO | Yes |
Vmkernel | 32 Bit | 64 bit |
Service Console | 32 Bit | 64 bit |
Concurrent remote console sessions | 10 | 40 |
Virtual Disk Thin Provisioning | No Thin Provisioning | Thin Provisioning introduced in vSphere 4.0 |
VMware Paravirtualized SCSI (PVSCSI | Not available | High-performance storage adapters that offer greater throughput and lower CPU utilization for virtual machines |
Hot Extend for Virtual Disks | Only Via VCLI using vmkfstools | Available via GUI |
Hot plug support for virtual devices | No | Yes |
VMXNET Generation 3 | Not Available | Yes |
vNetwork Distributed Switch | Not Available | Available from vSphere with Enterprise Plus License |
Private VLAN Support | Not Available | Available with DVSwitch |
Network Vmotion | Not Available | Available with DVSwitch |
3rd Party Distributed Switch Support | Not Available | We can use Cisco Nexus 1000v with DVSwitch |
IPv6 Support | Yes | Yes |
NICs per VM | 4 | 10 |
Standard vSwitches per host | 127 | 248 |
Virtual NICs per standard vSwitch | 1016 | 4088 |
8 way SMP | No Only 4 way | Yes |
Update Manager | Yes | Yes |
DPM | Experimental | Fully supported with PMI and iLO Remote Power On |
License Types | VMware Infrastructure Foundation VMware Infrastructure Standard VMware Infrastructure Enterprise | vSphere Essentials vSphere Essentials Plus vSphere Standard vSphere Advanced vSphere Enterprise vSphere Enterprise Plus |