Xeon or I7 for Virtual Machines and PCIe Passthrough

So I wrote the other day about changing over to Linux and choosing between AMD and Intel's Solution for hardware pass-through for VMs. Originally i had decided on waiting for the new zen models of AMD to come out. Now, after sleeping on it I have Decided to look more closely at the current Intel chips on the market.

Now getting to the point, for my use case i will be running the machine as a host for VMs that will be the Machines that I will be Using for day to day, etc. While also having the ability to run several VMs to do some networking Sims and generally playing around with/ learning with.
I want to know would it be worth getting a Xeon, the one that I'm looking at is the E5-2620v4 or would it be better to go for the I7s.

The Xeon's will give me more confidence in running the machine 24/7 when i need to. but the I7's also draw my eye.

What i really want is to see Your guy's opinions on which would be the smarter choice.

If you will never overclock, and will use more of the Xeon's features (ex. ECC), then go for the Xeon. Don't just go for the i7 because it has the fancy name behind it, because that would be stupid.


Go Xeon!

I really like this deal right now - http://www.ebay.com/itm/191828547222 (NOTE ITS RETAIL NOT ES). This is a great CPU for VM's (14c/28t) and for $350 you can't beat it. I have seen them as low as $300 though so look around on eBay.

You can pick up a decent SM board for $250 for a single socket, sever class. Any DDR4 ECC ram of your choice.

I would advise avoiding mechanical drives for OS storage. You can certainly use them for mass storage but investing in some cheap SSD's and creating a small SSD storage pool just for OS storage is highly recommended, there is a huge benefit there.

A used LSI 9260-8i would be a good investment as well, they can be had for $120 or so on eBay. Maybe a small RAID 5/6/10 mechanical array and two SSD's in RAID 1 for OS drives. But this really depends on your needs. If you don't need mass storage you can use the onboard SATA controller with the SSD's.

Note that most LGA 2011-3 server boards use narrow ILM so you will need to be aware of that when picking out your cooling solution.


Thank for the replies dudes.

Some nice food for thought

I was going to make a separate thread about this, but I picked up a HP Z420 workstation for 200 bucks on ebay. It Came with a xeon 1620v2 (only 4c/8t, but 3.9 Turbo) 16 gigs of ram and a K2000 card I turned around and sold for 100 bucks. With a BIOS flash it supported PCIE NVMe booting and VT-x and VD-d. Also tried a collection of Ranked ECC server dims I had, and they all worked.
That means 8 gig dimms can be had for cheap though ebay. As unbuffred are the expensive option.
Chucked the ram I had, and a rx 480 into this thing. Its a monster PC for cheap.

I also tested the NVMe booting, but have yet to get around to the passthough for windows VM setup.

1 Like

I guess this also adds another area for me to look at. do i require ECC ram or would non ecc work. seeing as none of the data would be, "mission critical" as some people put it. would having non ECC be fine. seeing as I'm going with the Xeon anyway and its an option to have. with the downside if it being so much more expensive per Gig.

Xeon all the way......just remember you need cores to share, not to sound like a broken record but it is so important that it deserves to be mentioned again, with a Xeon build like the E5-2620 for what the CPU sells for you could build a killer KVM machine using a dual Xeon processor server motherboard and have a entire 8 core /16 threads to pass to the KVM talk about bare metal performance....lol

Read this....


I would love to do something like that/this, however, just the current equipment that I will be investing in is going to stretch my budget

1 Like

Dual E5 2670. The old ones. Just get the right revision and you are golden.

Then let me take the i7 out of the equation for you, a i7 like a 6700k is a quad core processor and sells for $300-$400 retail, using this CPU the best you could hope to do is to pass through 3 cores and 12 threads to the KVM, while that might seem ok to you your talking about running some version of Windows and then programs on top of that or games and would probably realize the performance of a celeron CPU for your Windows experience, realistically you would only want to pass through 2 of the cores and 8 of the threads to the KVM and guess where that would land you performance-wise?

So say you go for the big guns and buy a i7 6900k now you are in the $1000 price range just for the CPU, yeah you get a 8 core /16 thread CPU but your paying a huge premium over the Xeon at a lower clock speed, you really want at the minimum a 6 core CPU so you can leave 2 cores for the host system while passing 4 cores to the KVM, what your trying to do here is duplicate the hardware you would run Windows on and in the example here it would be a low end quad core CPU.

It's this paradox that sent me over to AMD and buying a 8370, without going through all the Intel vs AMD on how they process instructions at the CPU level and how Intel is more efficient (it is) or how AMD doesn't have the same kind of threads (it doesn't) I found the AMD offerings better suited for what I wanted to do at the price point I was willing to invest..

My point is if you consider buying a octo-core i7 you have far surpassed the cost of a server mother board and 2 Xeons E5's just in the cost of the CPU alone......it's not how you want to invest your money, and if you want to be successful at this type of thing you need a octo-core CPU which the Xeon is, forget clock speed it matters very little in this application, this is all about numbers of cores/threads and how much memory you can throw at it, it's just that simple.

Hope this helps.

I disagree, this is a home server. Everyone recommends the old ass 2011 hardware for home use but never really thinks about the consequences of doing so. First thing first, the power, noise, heat, etc to run this older hardware is something to consider in a home environment. Sure you can throw it in your basement but you still have a ton of power usage = money.

You are "investing" in old and outdated gear. Why invest in old crap? You are going to spend at least $300-400 for used motherboard that BTW won't fit in just any case, another problem to worry about. For the same or less you can get into a high core single 2011-3 system which can be run with low wattage power and near silent cooling.

There is no upgrade path from 2011, what you get is what you get. At least with 2011-3 you could buy a high end dual socket board now, run a single CPU, and then upgrade by adding an additional CPU later on. I would much rather invest $600 into a dual socket current gen board now than literally waste $400 on a used dual socket 2011 board that BTW has no warranty.

Some may argue that by going with dual 2011 will be more powerful than a single 2011-3 and in some cases that may be true, but who needs that kind of power at home anyway? Does anyone need more than 20 threads for a home ESXi server? The 2011-3 CPU I linked to is 28 threads, two 2670 (assuming v2) would be 40 combined. Fairly certain the 2 for $100ish 2670's on eBay are v1's which would be 36 threads combined.

You'd have to run a newer system really long for it be worth it.


Correct. Power is a factor, that is where Intel made improvements, sure. But the higher initial cost is killing that argument.
Heat is barely a factor and so is noise if you know how to build computers.
This one is whisper silent even on full load and it runs in my living room.

I took naps next to it... noise is not a problem.
Here is the details.


If the OP was strictly talking about VMs I would agree with you, but the OP wants to do hardware pass through to a KVM (kernel based virtual machine) this application requires not the latest and greatest hardware but does require robust and powerful hardware to run both the host and guest systems concurrently, it's easy to build around VMs because everything is virtual but in a pass through where physical hardware is actually passed to the guest to use exclusively it becomes a little dicey and a little more complex with a few more considerations to make, of course the total cost is always a factor, if the OP was talking about just running VM's in like VirtualBox or some other hypervisor/VMM I would be recommending the same as you.

1 Like

As Blanger has said. The machine will be primarily doing hardware pass-throughs to a KVM.

1 Like

From my research But not having physically built one myself yet I believe you would want a processor with decent core/thread count but also you would want high clock speed with those cores. Are you wanting to do passthrough for gaming?

A bit of gaming, mainly a lot more as a test bench for me to try all this stuff on. If all goes well i would game on it and use it as the main system for Gaming and also for the fun of being able to make KVM's of different distro's and OS's that i can pass through hardware to, without the rigor of going through and re-imaging the machine each time i want to try something new.

Although in the end it is all a learning project to see if i have the ability to do this.

I think this question depends a bit on what the main goals are with the virtual machines.
If you want to use them for gaming, then maybe an i7 or a Xeon with some higher clockspeeds might make more sense, then a Xeon with more cores but lower clockspeeds.
However if gaming is not really a priority, but you mainly want to run multiple vm´s as smooth as possible, then sure a Xeon with more cores / threads will be benefitical.

Xeon E5-2620-V4 vs 5960X or 6900K, is really a matter of price diffrence.
If the price diffrence for the i7 isnt that significant, then i would probably go with one of those i7´s.
Because higher clockspeeds, and overclockability.
But yeah, that also depends on the VM usage ofc like i said above.

1 Like

In the end i went with the Xeon E5-2620-V4 because out of everything I've looked through it seems the most suitable for what i want. and i just fit perfectly into my budget after all the other purchases that i had to make this time.

1 Like

Let us know how it turns out.