Just interested if anyone has seen similar or what else I can try: I have an ebay r730xd that I’m migrating my current setup into. The CPU temp between CPU1 and CPU2 is consistently different, on early boot maybe only 4C difference but usually 7-10C different and trending higher depending on system load. I’ve seen this behavior using Ubuntu and Unraid as the OS (Unraid is the permanent OS, Ubuntu was for early testing). I’ve tried the following to isolate the issue:
- Swapped CPUs between sockets.
- Swapped coolers between sockets.
- Repeated reapplications of thermal paste on both CPUs.
- Inspected and juggled fans around.
- Inspected for any blockages in airflow.
In all tests there was no improvement: CPU1 remained the hotter CPU and the temperate delta between the two CPUs didn’t improve. At this point, I’m left thinking there is something wrong with the socket itself.
Has anyone seen this before and/or has any other ideas of what else to troubleshoot? I don’t want to get a new motherboard if I don’t have to but the temp of CPU1 triggers the fans to run too loud for apartment use but the temp of CPU2 would result in acceptable fan noise so I’ll take any advice.
Thanks
That sounds totally normal.
The airflow over the CPUs is not the same. My right CPU (as seen from the front) is always 2-4C hotter than the left. Under load, and if I have 16 spinning rust in the front, the right CPU may well be 4-5-6C hotter.
I wouldn’t worry about it.
CPU1 handles almost everything about being a normal computer: booting, chipset, most of the I/O, etc. CPU2 is along for the ride and handles its own I/O lanes (PCIe) and whatever work the kernel wants to send to it. The load is not symmetrical, so if you have turbo enabled, CPU1 will be consistently boosting more than CPU2 as it is handling all of its tasks —> warmer CPU1. This is why “tandem” dual-CPU setups have CPU1 upstream in airflow from CPU2.
In case any other panicked dell server noob shows up here with similar questions: even something as seemingly small as equal distribution of harddrives can impact temp. I only had 10 drives and filled the bottom two rows and top left two bays - right in front of CPU1. I moved the second from the left drive to the top-far-right bay and now the temps are balanced.