Mk1965,

The 2000-251 error just means that the BMC/hardware log has errors reported in it. Review the hardware log, save it, and then clear it. Afterwards the error won't be displayed. 

Let me know how it goes.

thank you for the reply.  I will try that and let you know.

but about the real error, the server just randomly reboots and then the LCD displays "CPU 1men vtt pg voltage is outside range"

this is what concerns me.

Make sure idrac and BIOS are up to date.

As Flash1932 stated make sure the server is up to date on BIOS and iDrac, also you may check over the server and make sure everything is seated firmly. 

update,

flashed bios and idrac, no change

lifecycle diags passed all but system management "issues with riser board" retest was fine.

reseated riser board.

but I have noticed that it ONLY reboots when running OS (win2012R2) while in bios or lifecycle management screen it does NOT reboot.  and yes windows up to date.

any other suggestions?

Any updates on this?  Mine is doing the exact same thing.  Everything is fine then once VMware boots throw that error and reboots.

Memory modules are all the same:

I have the same errors on my R520 ( 2x CPU, 128 GB RAM ).

Each time this error is logged, each time Windows crashes into BSOD and reboots (Kernel-Power event 41: "this system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed or lost power unexpectedly.")

Please advise.

After dealing with this problem for a year on an R420 and T420 running VMware 6.5 I found something that I hope may help today.  We had all Samsung memory in ours which we thought was a match.  The R420 was purchased along with extra DIMMs and when setup we installed some of the new memory into the T420 in order to bring both hosts up to 64G each.  Since the memory was "identical" it got installed into both servers.  Immediately we ran into problems and random reboots on the R420 and some time later the T420 as well.  Bios updates, extensive memory texting, re-seating every living thing in both machines, but nothing would point us in the right direction.  Today it happened again and I found this thread, upon further review I noticed some of our memory sticks were slightly different part numbers.  Both claim to be 1.35/1.5v on Samsung Datasheet, and both have identical specs except myself and 2 colleagues never noticed that the upgraded memory was indeed "low voltage" PC3L 1600Mhz and the remainder was not low voltage and was PC3 1333Mhz.  In theory none of this should matter but since I could not get the R420 to reboot I removed the PC33L sticks and it booted and so far so good.  Anyway, just thought I would pass it on as somehow 3 of us overlooked that and it seems like a likely culprit since this all started with the memory upgrade (and a slew of other changes which we exhausted every test method we could to rule out)

Here is what we missed on the part number:

M393B1K70DH0-YKO 8GB 2Rx4 PC3 Made in Korea

M393B1K70CH0-CH9 8GB 2Rx4 PCL3 Made in China

So received my R420 with 2 CPU and 4x4 micron PC3 1.5v and 4x4 hynix 1.3v on the 2.5.1 bios - ran like a rock.

Updated to 2.6.0 and it will not run with more than 24gb (6x4) in any "optimizer" 1234 or 1245 configuration or any combination of where the 1.3v and 1.5 v dimms land.

Complained so they sent me 8x4 hynix 1.3v. I can run 8x4 but if I try 12x4 - it craters again on the same error.

This appears to be related to the microcode patch - back flashing doesn't help. So it will require a bios/idrac update to fix.

When will Dell be releasing a patch to fix this?