seeking advice on optimized hardware for VirtualBox

[ginahoy]

I built my current desktop PC in 2007 (see sig). Except for an occasional browser compatibility issue, I still happily run WinXP. For my next machine, I plan go with Linux, with my 32-bit XP installation mounted in a virtual machine (to ease the transition).

When I built my current machine, I restored my previous OS (WinMe) into a VirtualPC VM. MS didn't support mounting an existing OS so I had to find help online from folks who had figured out how to do it. All I can say is that wasn't a project for the faint of heart, so I really appreciated finding a thread in this forum explaining how to do exactly that with VirtualBox! (since this is my first post, I can't post the link, but it's topic 15834) viewtopic.php?f=2&t=15834

For the time being, I'll use the Linux machine exclusively for browsing and continue using XP in VirtualBox for MS Office and other business apps, all of which are relatively easy on resources. I'm not into gaming, 3D CADD, video processing or other resource hungry apps, which is why I've been able to hold off so long on upgrading. However, I don't want to experience the sluggishness I had to tolerate with WinMe running in VirtualPC on my current machine. I anticipate that VirtualBox will be, by far, the most resource hungry app on my new system.

Since I don't follow advances in hardware tech, I need some advice on optimizing the hardware. For example, assuming no other apps running in the background, is there any performance advantage of, say, an 8-core CPU versus 4 cores? What about SMT (simultaneous multi-threading). Intel seems to be ahead of AMD in that regard. What about RAM? WinXP can only use 3+ GB, so is there be any advantage to installing 16GB or more, versus 8GB?

Bottom line, I don't want to spend a boatload of money on latest-greatest if it doesn't affect the performance of VirtualBox. So I'm hoping some knowledgeable hardware jocks hang out here who understand which h/w resources VB can actually take advantage of.

[mpack]

For example, assuming no other apps running in the background, is there any performance advantage of, say, an 8-core CPU versus 4 cores?
What about SMT (simultaneous multi-threading).

There may be an advantage to an 8-core CPU - if you want to run lots of VMs at once, or if a VM is running an app that has a use for multiple cores. I suspect that most do not have those requirements. In my case I usually only run one VM, and inside the VM I'm only focused on one single core app at a time, so generally I find that a 4 core CPU is perfect: 2 for the host, 2 for the VM.

And besides, genuine 8 core CPUs are rather hard to find, and expensive. Don't be fooled into thinking that threading has anything whatever to do with multiple cores (the only thing that VirtualBox cares about). Ask yourself: if threads equal cores then why do we ever need multiple cores?

p.s. I would avoid AMD 8 core CPUs: AMD rather controversially bent the definition of core (which to most means, multiple independant CPUs all on one chip) in order to make this numeric claim. I suggest that you research this, or stick to Intel.

What about RAM? WinXP can only use 3+ GB, so is there be any advantage to installing 16GB or more, versus 8GB?

You can never have too much RAM. This is far more important than number of cores. 16GB is fine, it will let you max an your XP VM without crippling your host.

You haven't mentioned disk space. You need a lot, and faster and bigger is better. I'd recommend that your PC has two drives, A good sized SSD, and a humungous secondary drive. E.g. in my own home PC I have a 512GB SSD, plus a 2TB hard drive. The VMs are located on the second drive.

Consider the host graphics card too: it acts as a graphics server for XP.

[ginahoy]

I appreciate the fast reply.

Re Cores: Sorry, I meant 2 cores vs. 4 cores. As I wrote that, I was looking at a Skylake table that shows cores/threads together so, for example, the Skylake desktop Core i7's are designated as 4(8). Your comment (re: 4 core CPU is perfect for VM) gives me something to work with. I think the advantage of SMT is power efficiency, so whatever performance improvement you get with 4(8) over 4(4) is 'free' in terms of power consumption. OTOH, performance improvements are hard to pin down since multi-threading can be used for various purposes in design. In any case, based on what I read this evening, I don't think anyone would argue that, say, a 2(4) can match a 4(4).

I should mention that power efficiency is my other primary objective in CPU selection (even more importantly, for graphic card selection). I built my current PC to be as silent as possible (with lots of help from the silentpcreview site, it wasn't too difficult since my PC is mainly used for browsing and office apps). I'm hoping to use an Intel CPU with rated TDP of 35W ("T" suffix).

You can never have too much RAM... 16GB is fine

Hmm... For an extra $50 or so, I can increase that to 24GB. Do you think there would be any performance benefit, given that my guest OS can only use 3+GB?

You need a lot, and faster and bigger is better. I'd recommend that your PC has two drives, A good sized SSD, and a humungous secondary drive. E.g. in my own home PC I have a 512GB SSD, plus a 2TB hard drive. The VMs are located on the second drive.

I will only have one VM. My OS partition is just under 40GB, but closer to 30GB once I clean up unused apps and remove the browser. So why not store the VM file on a secondary SSD? I already plan to use SSD for my primary Linux partition.

Graphics card selection probably deserves it's own thread since I need to keep power consumption (heat) to a minimum. My XP apps (or any of my apps for that matter) don't require much in terms of GPU performance. I plan to go with a passively cooled card (again). I plan tol use my existing modded case, which has a large (120mm) low-RPM fan mounted in the bottom, with RPM's controlled by GPU core temp sensor. I wouldn't think VirtualBox would put any additional load on the GPU. I guess that's a question.

[mpack]

I don't really want to get into a debate about the finer points of this discussion, because frankly the subject doesn't interest me much. I think I've given you my own opinions in answer to the original question, and you are certainly free to reject them or tailor them to your own priorities as you prefer.

I will say that I do understand the wish for a silent PC. I too self built a PC a while back with expensive components recommended by a silent PC site. I was very disappointed with the result: fan noise and an appallingly squeaky hard drive. Frankly, I don't think you don't really know how noisy something is going (or how annoying even small noises can be) until you put it all together, that's when you discover that the hd movements resonates with the case etc. On the other hand an off the shelf HP business midi that I bought next (having experienced them at work) was almost totally silent, even in a bedroom at night. Obviously putting the perfect package together is easy for HP. My current PC is also from HP (HP Envy 860-010), and isn't quite as quiet: the culprit is the fan in the top of the line graphics card they included, but it still knocks spots off that "silent" PC I bought. Never again.

[Antiphates]

My current PC has an Intel(R) Core(TM) i5-3570K CPU @ 3.40GHz and 16Gb RAM and the integrated Intel graphics - no high end games-playing graphics card. When I installed XP in a WM it flew along. That's not to say all applications on XP would, of course.

It had been fine on 8Gb until I decided I wanted to run an Oracle database and Weblogic inside one of the VMs (not the XP one). That setup only really worked with 8Gb for that particular VM so I upgraded to 16Gb for the host.

I also have a SSD/HD setup with 480Gb SSD and old HD with about another 400Gb and access to a NAS with 24Tb. You can set up a guest with multiple virtual hard discs and have one stored on the SSD (OS, for example) and one on the HD. You can't really split an existing image, though and well done at getting any verson of Windows from bare metal into a VM - windows seems to hate this kind of move whereas Linux is not fussed.

On the question of quiet the only effort I made with my tower PC was to check out the quoted noise level of the PSU and buy a quiet one. I have the HD spin down when not in use. It is noticably quieter than my laptop mainly because the laptop's fan is noisy. This should not be a great surprise because it is small and must therefore spin fast. To a first aproximation the noise made by a fan is proportional to the square of its speed whereas the amount of air it shifts is proportional to the product of speed and diameter. So each time you half the diameter and double the speed (thus shifting the same amount of air) you get four times the noise. That's why those slow-turning ceiling fans are so quiet.

[ginahoy]

@Antiphates, somehow I didn't receive notification email for your reply. Thanks for posting your system specs.

Is there any performance benefit to installing VirtualBox and/or the VM file on a second SDD? In particular, I'm wondering if the host OS and VB might ever compete for disk access while the VM is running. I don't envision using the VM and host OS simultaneously, so I'm guessing not. My preference would be to install a single SSD for the host OS and VM. I only plan to have one VM and I don't need any additional virtual HDD's.

My storage requirements are very modest... my XP machine (including OS/apps/data) only takes up 60% of a 50GB C: parition and my yet-to-be-built Linux host machine will also have modest storage requirements as it will only be used for browsing and for occasionally running the Plex media server. My video folder never accumulates more than 10 or 12 GB since I usually erase after watching. I'm thinking a 250GB SSD should be more than adequate for my needs. But if there's a performance benefit for separating the VM from the host OS, I could go with two smaller SSD's.

[mpack]

In particular, I'm wondering if the host OS and VB might ever compete for disk access while the VM is running.

An SSD can have have many more pending I/Os than an HDD can, and it can rattle through them at a rate of thousands of transactions per second.

An HDD has a limited number of heads, and those heads have to be physically moved to the site of the next I/O. There just isn't any sort of similar mechanical limitation with SSDs, so I'd say that you can forget the idea of VM contending with the SSD unless they're both trying to use 100% bandwidth at the same time: and I wouldn't shell out for a second SSD just for that eventuality.

IMHO, one fast drive and one bulk storage drive certainly meets all my requirements.

[ginahoy]

Thanks.