Newbie here... I am preparing for the RHCSA and need to setup virtual machines under Centos. I had originally planned on using a HP laptop as my physical host with vm machines, but discovered it did not support hardware-assisted virtualization. I am prepared to build a cost effective desktop but having a hard time determining the most cost effective (cheap) motherboard/cpu to use. Can someone recommend something for me? Thanks in advance.

It's not so much the board as it is the processor -- when you're looking for a motherboard, check the processor specifications. While you're at it, make sure you can plug in sufficient RAM; 4G on a 32-bit board is usually all right (most guest systems will run OK in 2G), on a 64-bit board you would probably want at least 8G, preferably more if possible although that depends upon what you're planning to do in the virtual machine(s).

Both Intel and AMD make processors with virtual capabilities, just make sure you check. Can't really recommend a particular brand of motherboard but there are a plethora available; be picky and choose the mostest-for-the-leastest. If it has a virtual-capable proc, it most likely has additional hardware to support what you want. And don't go overboard with cores, two is fine for most purposes.

Hope this helps some.

Depending on the VM you choose would be an issue also. I used to use some very old Pentiums and 586 systems to run older virtual machines. The cpu choice would seem to be the most important if you need hardware support. Without bios and motherboard chipset you can't make use of full hardware support.

I think I'd look for an older desktop if you can find one cheap. Most of the new low budget systems don't support hardware assisted features. Usually the office type used in businesses had vt-x and (forgot amd's name) in them.

I'd guess more of the amd systems have virtual support.

The last one I've built used the ASUS M5A 78L-M series with an AMD FX-6100 AM3 95W with 8G DDR3 which works well with Centos 6.3 64bit

The CPU AND the motherboard BIOS also needs to support virtualization.
Best to make sure that the motherboadr you are intending to use has a track record of people having success with it.

All current mobos support virtualization. And almost all CPUs. AMD at least has full support in all of its CPUs. With intels make sure you check, they have the habit of crippling their lower end CPUs.

Now, virtualization has major support levels:

- The commonly referred as Hardware virtualization - Intel VT-x / AMD-V.

This feature is exactly the same on both AMD and Intel CPUs, only it has different names. It enables the virtual machines to access all CPU features directly, making them work directly with the CPU without the need of emulation (called paravirtualization). Watch out for Intel CPUs, lower end ones sometimes have this feature disabled artificially.

- I/O MMU virtualization (AMD-Vi and VT-d) - the most interesting feature os IOMMU is the possibility to give direct access to actual hardware to the virtual machine (PCI passthrough).
BUT in order to use IOMMU one needs:
- CPU that supports it (not all CPUs that support Intel VT-x / AMD-V support IOMMU). For example the AMD Trinity APUs support it (at least the 4 core models). Also the Bulldozer series. Intel is, again, a hit or miss for desktop CPUs - the lower end CPUs dont support IOMMU usually.
- Chipset support - the motherboard's chipset has to support IOMMU. Usually higher end chipsets support it (i have a F2A85X-D3H mobo that uses the A85 chipset and it has support for IOMMU).
- BIOS support - the BIOS has to support this feature specifically (the chipset might support it, but if the BIOS doesnt, it wont be available)
- Kernel support - the kernel HAS to be compiled with IOMMU support.
- VM support - the virtualization solution has to support IOMMU.
Also, the device that is handed over to the VM has to be deconfigured beforehand.
http://en.wikipedia.org/wiki/IOMMU

I think all current AMD CPU/APUs have virtualization (AMD-V) enabled (maybe Semprons dont, but those are virtualy extinct anyway). You could build a computer around a A4-5300 APU for example with a A55 chipset board.

http://www.cpu-world.com is a good site to check for CPU capabilities.

Not sure I'd bet the farm on this. "All current mobos support virtualization" Each OEM would post that on their site. If not then assume it doesn't support any vm.

As with all technology, it ages fast. Each generation of vm's rely on more hardware support. Some of the very newest server boards offer the most advanced vm support. Many of the lowest models of systems including laptops do not offer hardware assisted vm's. I have not seen a system in almost 20 years that could not run some vm. I used bochs many many years ago to see a very slow system boot.

Virtualization support = support fot the CPUs virtualization features (AMD-V/Intel VT-x). This is required for *running VMs efficiently* with hardware assistance in ALL current virtualization solutions (VBox, KVM, etc.).
Other virtualization features such as IOMMU & co. are not *required*. Server boards have support for these, but for running VMs, they are *not* required.

PS. Qemu and VBox *can* run VMs without hardware virtualization. Only it will be slow and use much host-side CPU processing.
KVM requires hardware virtualization support. But anyway, if you plan on running VMs, hardware support is recommended to get the max performance/less overhead.

I guess we are saying the same things.

The OP's virtual experience would be best if they had a well supported system that included both hardware acceleration and enough resources like ram and disk space.