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Poor VM performance

Hello everyone

We have been fighting some odd VM networking issues with our 2012R2 HV cluster. To troubleshoot, I actually isolated one host and created 2 VM's, I then created a private vswitch and connected my 2 test VM's.

Here are the results I'm getting on a old NON UCS HV host. The host is an old PowerEdge 300. It's a single processor server with 4 cores... seriously It's a POS....

What has me concerned are the results of my test VM's on my UCS host

How is it possible for the VM's on our new B200M4 servers be under performing VM's on a 5y old m300?


Note: To perform my tests, I'm using TamoSoft's free test utility

8 Replies 8

Philip D'Ath

I have had so many problems over the years with Hyper-V and network performance.  Nearly always the problems are resolved by turning off all the networking smarts on both the physical hosts and the virtual machines.  Basically follow this guide and turn everything off.

In that doesn't resolve it, try upgrading the NIC drivers on the physical host.

The base VMWare package for three servers is only about USD$500.  Make the change.  You wont regret it.  The cost of ongoing Hyper-V support is just too high.

ps. You don't get these problems on older servers because they don't support any of the more advance hardware acceleration offload functions.  Hence why dumbing down new servers often resolves performance issues.

Hello and thank you for your reply. 

VMware VS Hyper-v is really not up to me here.. I have to identify the cause of this performance discrepancy and address it. That being said, my VM's are attached to a private switch, not associated with any physical adapters. So any advanced hardware offloading should not be at play here. Also, all the VM's were created with the same VHD image that was sysprep'ed. 


Kirk J
Cisco Employee
Cisco Employee


Can you tell me which processor model is in use and the blade firmware package installed?



Hello Kirk 

The servers are B200M4, processors are E5-2630V3 and the firmware is 2.2.4C. See complete details below.


I was suspicious you might be hitting , but that should be resolved in 2.24c

Just to confirm, your blade's BIOS and CIMC have a version # that say 2.24c, and not just your overall UCSM firmware release?



Hello Kirk, I'm familiar with that bug... were were affected. See case 636356017 if you need any additional details . 

Based on my tests, there is a very significant difference between 2.24b and 2.25b. It ranges from 20% to 60% better performance.

Is Cisco certain that the bug is completely addressed with 2.24b? 

See more details on my results here



Hello Kirk 

I'm still trying to get the to the bottom of this performance issue. I'm not sure why this made a difference, but I deleted the adapters from my VM's and then recreated them. Based on my notes, all settings in the VM and on host are identical. 

However, results of the last test is completely different. Based on these results, the B200M4 is clearly outperforming the M300! 


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