At this customer's site, there are two new Dell PowerEdge R320 servers with the following configuration:

  • A single 6-core CPU
  • 16 GB of RAM
  • 2x500 GB SATA disks in a RAID 1 array

The O.S. is Windows Server 2012 R2, used as a Domain Controller; all firmwares and drivers are up to date, and Windows is fully patched; the system load is usually very low.

All of a sudden, one of the servers slowed down to a crawl. And by "crawl", I mean "it wasn't even able to paint a window in a decent time". Doing anything at all, even right-clicking and showing up the contextual menu, even moving the cursor around, was an excruciating pain.

There was no unusual load on the server: CPU usage was 1-3%, RAM usage below 4 GB, no disk or network peaks, nothing at all.

There were also no errors whatsoever in any Windows event log (when we finally managed to open it), and the slowness didn't cease when the network cable was disconnected.

Rebooting Windows was useless, too: after a very long boot time, the system remained awfully slow as before.

Last but not least, there were no error messages either on the system's front panel display, or on the screen during the POST.

As a last resort, we decided to try a cold boot, and actually disconnected the power cables before restarting the server. This fixed the problem: the system booted normally and resumed full performance.

However, the question remains: WTF happened here?!?

And, more important: how can we make sure it won't happen again?

  • 1
    First thing that comes to my mind would be running the Dell diagnostic tools to see if there's a hardware fault or impending failure. – HopelessN00b Oct 31 '14 at 18:18
  • Have you tried running the F2 Diagnostics, your ECC ram could be having issues. – zillabunny Oct 31 '14 at 18:24
  • Had the same issue with an R320 - windows rebooted from a small batch of 8 Windows updates and the server rebooted but was extremely slow and my Exchange 2013 services including the Exchange RPC service wouldn't start. Warm reboots didn't change anything and events logs were ambiguous and slow to read so it appeared as if the Windows Updates were the cause. Luckily, I took a step back and researched the slow issues with Win 2012 and Dell R320 and found your post. A cold boot and clearing the power fixed the speed issues and the Exchange services all started correctly. I could only conclude tha – user281916 Apr 16 '15 at 0:22

Had identical problem, after examining DSET logs while issue was present and then after cold boot fix, Dell support claimed power surge, server powered by APC 1500kVA SmartUPS at the time.

Dell support recommended cold boot to reset sensors (power unplugged, hold down power button for more than 3 seconds).

Support also suggested patching iDrac to latest available 1.66.65 either through Lifecycle (requires reboots) or from Windows system (does not require reboot).

This happened a few weeks ago during first week of January 2015, problem has not returned.


Dell PowerEdge R320 6-core CPU 24 GB of RAM 2 x 1000 GB NLSAS disks RAID 1

  • I too had an R320 with the CPU usage maxed out at 100% (1.28.2015), yet no foreground applications were running. It was too slow to even run a virus scan. I rebooted into 'normal' mode and the R320 is still much faster. Running one instance of Chrome (one tab), CPU usage is now 0~1%. The R320 has a Xeon E5-2407 processor, 8GB RAM, 4 SATA 500GB and 1TB drives RAID 1 config. Server 2008 R2 and APC 1250VA BACK-UPS with no events since 11/26/2014 – user267498 Jan 28 '15 at 18:31

I have 2 Win2K12-R2 T320's with same hardware, firmware and drivers. Yesterday one became painfully slow - no Windows updates installed in weeks. After running a DSET with no hardware errors:

Dell tech recommended Going into the BIOS on the T320, go into System Profile Settings and change 'Performance per Watt' to 'Performance'

Rebooted and server is running fast and performance is better than it has been in months.


I would start with updating all firmware versions to the latest available, including the BIOS, iDRAC/Lifecycle Controller. This is more likely an issue with the power usage & performance settings in the BIOS though. Check out the Performance and Power Tuning doc for Dell 12th gen servers for details.


This happened to our T320. It was a bug in the bios. Dell released an updated bios and the issue was fixed. A workaround is to set the bios as follows: In the PowerEdge Bios, change the System Profile to Performance Optimized. This will disable C-States and C1E. Instructions: http://www.ponjavic.com/wordpress/2014/09/30/disable-dell-poweredge-m620-cpu-throttling/

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