UnRAID on 8th Gen Core i7


garycase

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I'm thinking of building a new server using an 8th gen Coffee Lake CPU [6-core Core i7-8700k].

 

Just curious if anyone's already using this CPU or another 8th gen processor and if there are any known issues with these with UnRAID.

 

I'm debating between this and a previous gen Xeon E3 ... I'd much rather have the ECC support of a Xeon, but the 16229 PassMark of the 8700k is very tempting.    But before deciding, I thought I'd see if anyone has confirmed that the 8th gen CPUs don't have any known issues.    I don't want to suffer "early adopter" issues like those who built Ryzen systems had to go through :D

 

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.... one other thought related to this question:    I know that 7th and 8th gen Intel CPU's are excluded from getting updates if running Windows versions earlier than Win 10.    This is also an issue with virtual machines running on systems using those processors -- at least in the VMWare world.     Do UnRAID VM's have the same issue when running on 7th or 8th gen hardware?    There's a workaround using a utility [WUFUC] that masks the CPU flag, but I'm curious whether or not this capability might be a built-in option for UnRAID virtual machines.

 

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I'm shocked! Server without ECC!!! OMG!

 

I recently bought a new i9-7920X. Intel doesn't put into 8th generation, but same vintage. Working on a detailed writeup on my build. 

 

I've had good luck. IOMMU groups working well. Very fast. 12 4.5GHz full speed cores. Cinebench is 3004 (8700k is 1432 from what I found online - about half which makes sense since half the cores). My 4 core Xeon 1270v3 running the bench in a VM (3 cores) was about 450. 7920x on 11 core VM about 2750. That's a big difference! Haven't done passmark yet - I think it factors GPU score and I directly have crappy GPU to get it set up. Cinebench is pure CPU score.

 

I would think that the Linux microcode patch would take care of the VMs in the KVM. Also, the VMs are build on a virtual architecture of an i440fx which looks like a Pentium II vintage chipset. Not sure what if anything Windows would do with something that old. The passed through processors do include the actual processor model so it may recognize it as as VM and know the processor. Don't know. 

 

I'd say go for it. Might look at the 7820x, 79X0x of you'd like more cores. I tend to buy just behind the state of the art where the price performance curve sort of flattens out. For me that was the 7920x. Finding one on eBay, delidded by Silicon Lottery, for $930 (retail would have been $1240 with professional delidding) convinced me this was the right chip. 

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1 hour ago, SSD said:

I'm shocked! Server without ECC!!! OMG!

 

You did note I said ...

 

2 hours ago, garycase said:

I'm thinking of ...

 

I also noted I was torn because of the lack of ECC -- and haven't actually decided yet.    I've been looking for the 8th gen E3 Xeons, which should have similar performance AND ECC.

 

The i9's are also tempting, but I have a hard time convincing myself to spend over $1K on just the CPU  (which, in the great scheme of things, is irrelevant, but I just have this mental reservation about that number.)    The 23482 PassMark for your i9 is indeed a very nice number :D.    [Not sure why, as I once spent about $1200 for a 4K  (yes, "K") memory board (circa 1976) that, in today's dollars is about $5000 !!]

 

As for the VM's -- VMWare emulates an older chipset as well; but the actual CPU model is passed through to the VM, and it will cause the "no updates" issue on Win7 or Win8 VMs on 7th gen or later systems (I've had this issue on a 7th gen -- don't have any 8th gen units to try).    The WUFUC utility resolves this -- I was just curious if this would also be needed on the KVM Vm's.    Sounds like it would.   Not a big deal, I was just curious if there was a KVM option to NOT pass through the actual CPU type.

 

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On any Windows OS you can do a "Properties" on "Computer", "My Computer", "This PC"  (depending on version) and it will show what the CPU is.    With VMWare this will always be the actual CPU, even though the emulated chipset is an old chipset that doesn't actually correlate with any modern processor.    But if the CPU is a 7th gen or later Intel, then Windows 7 and Windows 8 will NOT do the latest updates.   [As I noted, this is easily bypassed by first running the WUFUC utility.]

 

I suspect that KVM reports the real processor as well -- but I don't have any KVM VM's, so don't know for sure.    Anyone with the virtual Windows 7 or 8 machine could answer this by simply doing a Properties and confirming that the CPU that's shown is the actual CPU in the system (or not).

 

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I haven't paid close attention, so I'm not sure of the details, but the OSX guys always had to specify a specific CPU in the XML to fool the OS into running. The same technique should work for windows.

9 hours ago, garycase said:

Anyone with the virtual Windows 7 or 8 machine could answer this by simply doing a Properties and confirming that the CPU that's shown is the actual CPU in the system (or not).

If they choose the defaults, it WILL show the actual CPU. It requires manual intervention to change that, as I said previously. What I don't know is what the base emulated CPU is, if you don't specify the one you want to emulate in the XML. It very well may emulate the actual CPU you are running, but that is changeable with XML edits.

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  • 7 months later...
On 1/23/2018 at 7:46 PM, garycase said:

 

You did note I said ...

 

 

I also noted I was torn because of the lack of ECC -- and haven't actually decided yet.    I've been looking for the 8th gen E3 Xeons, which should have similar performance AND ECC.

 

The i9's are also tempting, but I have a hard time convincing myself to spend over $1K on just the CPU  (which, in the great scheme of things, is irrelevant, but I just have this mental reservation about that number.)    The 23482 PassMark for your i9 is indeed a very nice number :D.    [Not sure why, as I once spent about $1200 for a 4K  (yes, "K") memory board (circa 1976) that, in today's dollars is about $5000 !!]

 

As for the VM's -- VMWare emulates an older chipset as well; but the actual CPU model is passed through to the VM, and it will cause the "no updates" issue on Win7 or Win8 VMs on 7th gen or later systems (I've had this issue on a 7th gen -- don't have any 8th gen units to try).    The WUFUC utility resolves this -- I was just curious if this would also be needed on the KVM Vm's.    Sounds like it would.   Not a big deal, I was just curious if there was a KVM option to NOT pass through the actual CPU type.

 

Did you end up trying an 8th gen build? Just went this route myself. Tired of paying the extra power bill for my dual xeon beast.

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