i7 6500u vs i7 7500u Virtualbox support

[arnix]

Hi all I'm new here. I'm planning to buy a laptop with i7 6500U/7500U processor and 8GB RAM. Now my question is that how good is these ULV class cpus for virtualization? As I've heard in other Hardware related forums that i7 6500U/7500U will not be a good idea if I'm going to virtualization due to their lower TDP. Is it true? In my current system I've Opensuse as my main os and windows 7, ubuntu, os x as guest os. So should I need to invest a large chunks of money for a high power processor or i7 650U/7500U would be perfect. Please suggest I'm in great confusion.
Thanks in advance

[scottgus1]

No idea what ULV and TDP mean. The faster the CPU, the less of a bottle-neck it may be. (Fast doesn't always mean GHz, it also means bigger Caches, etc.) The CPU should also have VT-x, and so should the BIOS of the laptop. If either CPU or BIOS doesn't have VT-x you will be limited to 32-bit one-virtual-cpu older-than-windows-8.1 guests, and maybe some limitations in Linux, too, I don't know.

Virtualbox is an application running on your host PC's OS, so VB will be subject to the CPU counts and RAM limitations of the host OS.

You should not count hyperthreading when counting physical cores. A four-core Core-I7 with hyperthreading has four cores for Virtualbox purposes, even though the host OS may show eight.

A guest should not be set to have the same or more cores than the host has, even if the Virtualbox Settings will allow you to do so. So on the four core I7 mentioned, no guest should have more than three cores. The host must always have a core to use for itself. It is possible to have multiple guests that each have less than the full amount of cores but total up more cores than the host has as long as the guests don't all go full-throttle at once. (eg: I have run two 2-core guests, and a one core guest = 5 cores for guests on a four-core I7, with no problem, because the guests weren't always heavily using the cores.) It's a risk, time will tell how many guests you can run at the same time.

Ram usage is simple math: the total amount given to guests + the host's non-Virtualbox requirements < total host ram. There are some tricks to move ram between guests while running the guests, but live hot-swap from host to guests after the guests have been started is not possible, and you can't get more ram than the host has. Disk swap files don't count.

Expect disk bandwidth limitations and sluggish data access in the guests when booting or heavy-running more than two modern OS guests on one platter drive at the same time. The head just can't move around fast enough. SSDs eliminate this problem.

[mpack]

TDP is not an acronym I was familiar with either, but I found this on Google and suspect this is what it refers to :-

https://en.wikipedia.org/wiki/Thermal_design_power

Obviously this parameter would be more noticable to users of mobile devices, whereas I do my main work on a desktop.

I assume the relevance is to the assumption that if you were to max out all the cores then the heat output of a mobile processor might go up to the point that it becomes capped. But, I think if you're maxing out all cores at once then you've probably got lots of things going wrong. I guess it might matter if you were planning to run 50 VMs on a 4 core host.

It's a parameter certainly, but it seems to me that I shouldn't weight it too highly in my decision.

I assume that ULV means ultra low volts == mobile device, so I won't bother to look that one up.

[BillG]

There are lots of things apart from the CPU which will affect vm performance on a laptop. I would be more worried about the disk drives. (And I would not mention the OS X vm again).