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Should a first generation Xeon Skylake Silver 4110 work with 2993 MHz RAM?

drkirkby
Beginner
589 Views

I have a Dell 7920 which came with a single Xeon Silver 4110 CPU

https://ark.intel.com/content/www/us/en/ark/products/123547/intel-xeon-silver-4110-processor-11m-cac...

The data on the CPUs says "Memory types DDR4-2400, speed 2400 MHz"

I have a problem with the Dell, in that it will not power on if there's a DIMM in slot 4, of the 1st CPU. (Also one of slots 5 or 6, but not both). I can only get 4 memory channels to work with a single CPU.

I have verified the problem with two sorts of CPUs

* Single 4110 silver (8-core 2.1 GHz), which is a first-generation chip, supplied with the Dell

* Single Platinum 8167M (24-core 20 GHz), which I assume is a first-generation chip but is a "secret" OEM special that Intel wont say much about.

* Dual Platinum 8167Ms

Irrespective of what CPU(s) I use, the machine will not boot with a DIMM in slot 4.

Someone pointed me to a document from Dell that said the Skylake processors did not support 2933 MHz RAM. That document must be quite old, as clearly lots of the high-end processors like the 8280

https://ark.intel.com/content/www/us/en/ark/products/192478/intel-xeon-platinum-8280-processor-38-5m...

can use 2933 MHz RAM to their benefit.

The RAM I am using is Kingston KTD-429/32G (32 GB RDIMM, 2933 MHz). Kingston tells me that's a suitable RAM for the Dell 7920. Should 2933 MHz RAM be okay with a CPU that can't run that fast? I assume the 2933 MHz RAM would just jog along at 2400 MHz, and have an easy life, not working too fast. But could 2933 MHz RAM present a problem with that CPU?

I think its a bit unlikely to be a RAM issue, as when I use the dual 8167Ms I can put DIMMs in slots 1, 2, 3 and 4 of the second CPU, but not the first.

The problem always seems to follow the motherboard - changing CPUs or RAM  locations does not change the problem. I'm just trying to eliminate all possible causes.

My biggest problem is the machine is under warranty, but getting support from Dell is going to be "tricky" when I use Kingston RAM. But Dell wants a fortune for RAM.

Dave

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7 Replies
n_scott_pearson
Super User Retired Employee
571 Views

When you have a processor rated for a maximum speed of 2400 MHz, using XMP to enable 2993 MHz operation is (a) technically a form of overclocking and (b) not guaranteed to work. You are correct when you say it is going to be *very* dependent upon the individual processor, motherboard and DIMMs present. I will go further and say that what works today may not work a year from now.

All components introduce some amount of (electrical) noise. As the memory buses are sped up, even more noise can be introduced onto the buses. Worse, as these components age, they will produce higher and higher amounts of noise. Motherboards are designed to try and limit this noise. They do so with things like termination resistors to avoid reflection, etc. Regardless, if the combined noise on the memory buses reach levels where the Memory Controllers in the processor or in the DIMMs themselves cannot distinguish the noise from the data, then transfers will fail and buses will hang.

So, opinion time. I think that it is unreasonable to assume that a processor intended for 2400 MHz is always going to work when presented with 2993 MHz DRAM. That is a 20% increase in clock frequency; pretty significant. Further, as I said, if it happens to work now, there is no guarantee that it will continue to do so a year from now as noise levels rise.

Hope this helps,

...S

drkirkby
Beginner
565 Views

@n_scott_pearson  I did not know what XMP is, so I had to Google it. I see it is Extreme Memory Profile.  I gather it is a setting in the motherboard BIOS that allows one to make memory run faster.

https://www.tomshardware.com/reviews/how-to-enable-xmp-ddr4-overclocking,6133.html

As far as I can understand from that, it is something someone would need to change in the BIOS to make the memory run faster. But I have not done that. I doubt a Dell motherboard for a workstation with error-correcting RAM would even have such settings. The Dell 7920 is not a typical PC - not too many PCs can take 3 TB of RAM or are available in a rack-mount version with redundant power supplies

If I go to the Del website,

https://www.dell.com/en-us/work/shop/desktops-all-in-one-pcs/precision-7920-tower-workstation/spd/pr...

I  can configure a Dell 7920 how I want to order it. A fully configured one costs over $100,000. The standard CPU is

Intel Xeon Bronze 3204 1.9GHz, ( 6C, 9.6GT/s 2UPI, 8.25MB Cache, HT (85W) DDR4-2133) It  comes as standard with 16GB 2x8GB DDR4 2933MHz RDIMM ECC Memory,

So that's a slow cheap processor that comes as standard with 2933 MHz RAM.

I am not trying to push the RAM to run faster. I assume the speed the RAM runs at would be dependant on what it is driven at. The RAM does not have its own oscillator that forces it to run at 2993 MHz, does it?

I'm not intending to make anything run faster.

Dave

n_scott_pearson
Super User Retired Employee
562 Views

I don't profess to be an expert on the server side, but I ask: Why do you want to pay for this faster DRAM if you cannot make use of its speed anyway? Why purchase anything faster than 2400 MHz if it isn't going to be used that way?

...S

drkirkby
Beginner
554 Views

@n_scott_pearson The reason for wanting to use 2933 MHz RAM is that the system supports CPUs that use 2933 MHz RAM. At a later date, when the prices of CPUs fall, I intend to get a pair of CPUs that will make full use of 2933 MHz RAM. The following CPUs can all be bought from Dell with the 7920 workstations, which runs at 2933 MHz. See

https://www.dell.com/en-us/work/shop/desktops-all-in-one-pcs/precision-7920-tower-workstation/spd/pr...

  • Intel Xeon Gold 5222 3.8GHz, ( 3.9GHz Turbo, 4C, 10.4GT/s 2UPI, 16.5MB Cache, HT (105W) DDR4-2933)
  • Intel Xeon Gold 6226R 2.9GHz, ( 3.9GHz Turbo, 16C, 10.4GT/s 2UPI, 22MB Cache, HT (150W) DDR4-2933)
  • Intel Xeon Gold 6226R 2.9GHz, ( 3.9GHz Turbo, 16C, 10.4GT/s 2UPI, 22MB Cache, HT (150W) DDR4-2933)
  • Intel Xeon Gold 6234 3.3GHz, ( 4.0GHz Turbo, 8C, 10.4GT/s 3UPI, 24.75MB Cache, HT (130W) DDR4-2933)
  • Intel Xeon Gold 6234 3.3GHz, ( 4.0GHz Turbo, 8C, 10.4GT/s 3UPI, 24.75MB Cache, HT (130W) DDR4-2933)
  • Intel Xeon Gold 6238M 2.1GHz, ( 3.7GHz Turbo, 22C,10.4GT/s 3UPI, 30.25MB Cache, HT (130W) DDR4-2933)
  • Intel Xeon Gold 6246R 3.4GHz, ( 4.1GHz Turbo, 16C,10.4GT/s 2UPI, 35.75MB Cache, HT (205W) DDR4-2933)
  • Intel Xeon Gold 6246R 3.4GHz, ( 4.1GHz Turbo, 16C,10.4GT/s 2UPI, 35.75MB Cache, HT (205W) DDR4-2933)
  • Intel Xeon Gold 6250 3.9GHz, ( 4.5GHz Turbo, 8C, 10.4GT/s 3UPI, 35.75MB Cache, HT (185W) DDR4-2933)
  • Intel Xeon Gold 6252 2.1GHz, ( 3.7GHz Turbo, 24C, 10.4GT/s 3UPI, 35.75MB Cache, HT (150W) DDR4-2933)
  • Intel Xeon Gold 6252 2.1GHz, ( 3.7GHz Turbo, 24C, 10.4GT/s 3UPI, 35.75MB Cache, HT (150W) DDR4-2933)
  • Intel Xeon Gold 6256 3.6GHz, ( 4.5GHz Turbo, 12C, 10.4GT/s 3UPI, 33MB Cache, HT (205W) DDR4-2933)
  • Intel Xeon Gold 6258R 2.7GHz, ( 4.0GHz Turbo, 28C, 10.4GT/s 2UPI, 38.5MB Cache, HT (205W) DDR4-2933)
  • Intel Xeon Platinum 8253 2.2GHz, ( 3.0GHz Turbo, 16C,10.4GT/s 3UPI, 22MB Cache, HT (125W) DDR4-2933)
  • Intel Xeon Platinum 8260 2.4GHz, ( 3.9GHz Turbo, 24C, 10.4GT/s 3UPI, 35.75MB, HT (165W) DDR4-2933)
  • Intel Xeon Platinum 8260L 2.4GHz,(3.9GHz Turbo,24C,10.4GT/s 3UPI, 35.75, HT (165W) 4.5TB DDR4-2933)
  • Intel Xeon Platinum 8260M 2.4GHz, (3.9GHz Turbo,24C,10.4GT/s 3UPI, 35.75, HT (165W) 2.0TB DDR4-2933)
  • Intel Xeon Platinum 8268 2.9GHz, ( 3.9GHz Turbo, 24C, 10.4GT/s 3UPI, 35.75MB, HT (205W) DDR4-2933)
  • Intel Xeon Platinum 8270 2.7GHz, ( 4.0GHz Turbo, 26C, 10.4GT/s 3UPI, 35.75MB, HT (205W) DDR4-2933)
  • Intel Xeon Platinum 8276 2.2GHz, ( 4.0GHz Turbo, 28C, 10.4GT/s 3UPI, 38.5MB, HT (165W) DDR4-2933)
  • Intel Xeon Platinum 8276L 2.2GHz, (4.0GHz Turbo,28C,10.4GT/s 3UPI, 38.5MB, HT(165W) 4.5TB DDR4-2933)
  • Intel Xeon Platinum 8280 2.7GHz, ( 4.0GHz Turbo, 28C, 10.4GT/s 3UPI, 38.5MB, HT (205W) DDR4-2933)
  • Intel Xeon Platinum 8280L 2.7GHz, (4.0GHz Turbo,28C,10.4GT/s 3UPI, 38.5MB, HT(205W) 4.5TB DDR4-2933)

So there are quite a few CPUs available from Dell that fit this workstation but use 2933 MHz RAM. I don't fancy spending lots of money on 2400 MHz RAM, only to have to change it when updating a CPU. The RAM is the most expensive item in that machine. To get maximum capacity one needs to use LRDIMM. 3 TB of that adds more than $92,000 to the price of a 7920! 

 

n_scott_pearson
Super User Retired Employee
546 Views

First of all, you don't need to call me out in every post; I get notifications of your responses regardless (and really don't need to be getting two)...

It sounds to me like you are, as they say, 'stuck between a rock and a hard place'. The faster memory is not working with this processor. Do you go for a different processor or purchase slower memory? If you purchase slower memory, you are stuck with this memory speed even when you have a processor that could make use of the faster speed. Hhmmm...

Have you checked whether there are parameters in BIOS Setup that will allow you to override the memory speed from Auto to, say, 2400MHz? I have no idea if 3rd-party Server boards support this capability as Desktop boards do.

If that isn't possible, well, I have exhausted my thoughts regarding alternatives. If Intel Customer Support will move this conversation into the Servers forum, we can get a better mindset thinking about this issue...

...S

drkirkby
Beginner
541 Views

I'm not convinced it is a processor issue. I have 3 CPUs, all of which have the same problem, on the same memory channel, although none of the CPUs are 2933 MHz.

I did not ask about the other two CPUs, as those are two CPUs are OEM devices that Intel will not release any information about. But I have a pair of Platinum 8167Ms (26-core, 2.0 GHz) too. The BIOS shows the memory speed as 2400 MHz with those - see photograph.

Intel wont say what the memory speed of that CPU is, but 2400 MHz seems a reasonable number, and the BIOS shows that's the RAM speed, despite the actual RAM itself is 2933 MHz. So I assume the RAM with the Platinum 8167Ms is clocked at 2400 MHz, and the Silver 4110  is probably clocked at 2400 MHz too, although I have not actually checked what the BIOS says.

The attached photograph is not meant to demonstrate a good way to use RAM - I know it is not. But it demonstrates that the 2nd CPU sees DIMMs in slots 1, 2, 3 and 4. But the first CPU will not work with a DIMM in slot 4. Swapping the position of the two Platinum 8167M CPUs around does not change anything. It is still DIMM socket 4 of the first CPU that's presenting the problem.

I know its not a conclusive proof, but it is odd if a DIMM is in socket 4 of the first CPU, the system will not work with either

* 1 x Silver 4110

* 1 x Platinum 8167M

* 2 x Platinum 8167Ms

If it was a problem on the 8167M CPU, one might reasonably expect the problem to move if the positions of the CPUs are swapped over, but that's not the case. I only have one Silver 4110, so can't change the position of that.

Dave

JoseH_Intel
Moderator
523 Views

Hello drkirkby,


Thank you for joining the Intel community


As per ark.intel.com the maximum supported memory speed is 2400 MHz. Any alternate configuration is considered as not supported. For any other questions related to population or technical assistance should be provided by the board vendor OEM.


Intel® Xeon® Silver 4110 Processor (11M Cache, 2.10 GHz) Product Specifications


Regards


Jose A.

Intel Customer Support Technician

For firmware updates and troubleshooting tips, visit:

https://intel.com/support/serverbios


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