I7-6700K or 2700X for a new Unraid Server


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Hi, I'm looking to set up another home server with Unraid.   I'm looking at either using a used 4-core I7-6700K or a getting a 8-core 2700X.   I plan to running 4 or 5 VMs at the same time plus a few dockers.    Will a I7-6700K be adequate or should I go for a 2700K.   I'm not sure if the extra cores with be beneficial.   Thanks!

 

David

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16 hours ago, davidst95 said:

Hi, I'm looking to set up another home server with Unraid.   I'm looking at either using a used 4-core I7-6700K or a getting a 8-core 2700X.   I plan to running 4 or 5 VMs at the same time plus a few dockers.    Will a I7-6700K be adequate or should I go for a 2700K.   I'm not sure if the extra cores with be beneficial.   Thanks!

 

David

If you are going to run 4 or 5 VMs simultaneously (of course, depends a lot on what they are and what they are doing), even an 8-core/16-thread Ryzen 2700X may not be enough.  For lots of dockers, either will work fine. 

 

You will want to pin cores/threads to VMs if running them simultaneously.  Remember unRAID still needs CPU cores allocated to it as well.  You may be OK with an 8-core/16-thread CPU if your VMs are light use, but, 4-5 simultaneously + unRAID could put you in a CPU crunch if the VMs demand a lot of CPU power.

Edited by Hoopster
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Each VM need at least a dedicated core... 4-5 Cores away.

Your unraid basesystem need at least one (better two) cores.

If you need "really" 5 VMs (for whatever), take a Xeon with 10-12 Cores or more because in such a config, you need also ECC-RAM.

And beware the RAM-size - you will need a lot of RAM...

Edited by Zonediver
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1 hour ago, Zonediver said:

Each VM need at least a dedicated core... 4-5 Cores away.

Your unraid basesystem need at least one (better two) cores.

If you need "really" 5 VMs (for whatever), take a Xeon with 10-12 Cores or more because in such a config, you need also ECC-RAM.

And beware the RAM-size - you will need a lot of RAM...

Thanks for the info.  I thought you don't really need ECC Ram in the Zen chips because they automatically correct errors in the cache.

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17 hours ago, Arbadacarba said:

When you say the base system needs one or two cores do you mean core and hyperthread pairs? Or One core plus it's hyperthread?

 

I have the 6700k and was just thinking I should go through my VM's and make sure to leave a set of cores out of all of them... Basically leave it for the 

unraid server.

First of all, i dont use VMs - i use all the cpu-power for Plex-transcoding.

But what i did: I pinned the cores to different functions - you can do this at the docker settings - each docker has its own cpu-pin setting.

The i7-3770 has 4 cores + 4 HTs.

I use the first core + HT for unraid and my dockers - beware: unraid preferes the lower core numbers starting from core 0!

VERY IMPORTANT: Do not mix the physikal cores with "wrong" HT-cores.

Example: Core 0 and core 6 (on my CPU) - thats a NOGO because it is slowing down things. Always match the "right" cpu-pair.

The other three cores (+HT) are pinned to Plex for transcoding.

This setting gives the base system enough air to work - even if Plex is 100% transcoding.

 

Core-pinning:

1st Pair - Core 0 and 4 (HT) ... unraid and all dockers except Plex

2nd Pair - Core 1 and 5 (HT) ... Plex

3rd Pair - Core 2 and 6 (HT) ... Plex

4th Pair - Core 3 and 7 (HT) ... Plex

 

INFO: There is no way to restrict or determine cores for unraid itself. Unraid starts at core 0 and uses as many as needed - normaly up to 2 or the first pair (physical and HT), sometimes a third. If you do a parity check, it is recommended to turn off all VMs and dockers (if possible) to give unraid itself "more power" to work.

Edited by Zonediver
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