I had already decided to use a Xeon 1245 v5 on a C236 board the (the Supermicro MBD-X11SSM-F-O to be specific)

 

I had heard that Skylake was not a good platform for VMs but I figured that was with Z170 and C232 but that with C236 I'd be ok.

 

Today I went looking to see if you could pass-through IGD and the answer appears to be no which is fine except again there was a discussion of Skylake for VMs and again people recommended against it.

 

My use is as follows -- Windows 10 machine with pass-through / 2 VMs that will be headless / small NAS + a couple of dockers.

 

Based on some of the reading I've done the main issue with Skylake is ACS -- is that a concern if only one VM is going to use pass-through?

 

Would I be better off with a v3 Xeon than a v5?

 

I've learned a lot in two weeks of reading these forums but I'm still way out of my depth on this so if someone could help me out it would be greatly appreciated.

 

As far as price is concerned the v3 and v5 are roughly the same (CAD$400.97 vs CAD$429.99) but I want 32GB of ram and Have been informed that I want to use only two sticks so that is 16GBx2 which isn't an issue for v5 motherboards but for v3 most I saw would have to be 8GBX4.

 

If the device(s) that you want to pass to a VM are within their own IOMMU group (or all of the ones you want to pass are in the same group), you shouldn't have an issue.

The issue is if the device(s) you want to use in a VM are grouped with other devices, as it is an all or nothing kind of thing for it to work.

If you do not have this issue, then you should be fine (there is no great way to know other than testing, or asking someone with the same hardware you're considering).

 

If you do have this issue, apparently the patch for ACS override does not work with Skylake at this time (however another user said it does work for him, but I'm uncertain of those details), but keep in mind this isn't "recommended" but likely a fine alternative for those who need this option.

 

If you already have a Skylake build, I would think that you shouldn't have much issue (without seeing grouping, I am guessing a bit) getting a single VM with pass through going, and other headless VM's up to as many as reasonable given ram/CPU concerns.

 

The V3 Xeon does not support ACS on root ports, which is what ACS is all about.

However, again, for 1 VM with pass through, your grouping of IOMMU groups may work out well with little to no issues (this is hit or miss with MB/CPU's, this is the same situation for Skylake or v3 Xeon) The V5 has ACS on root ports, plus other bells and whistles.

 

I think the bigger question to ask yourself if you're looking at Xeon's, is the addition of ECC memory.

Certainly something that is better to have than not, but again, what kind of $$ do you plan to spend on this?

 

If you don't want ECC memory (not getting into this debate, however again it is certainly better to have than not), but want ACS on root ports, I'd recommend the "old" Haswell i7 "Extreme" processors which have ACS capabilities.

You really can't go wrong with the E5 other than price.