Can GPU capabilities impact virtual machine performance?

Question

While this many not seem like a programming question directly, it impacts my development activities and so it seems like it belongs here.

It seems that more and more developers are turning to virtual environments for development activities on their computers, SharePoint development being a prime example. Also, as a trainer, I have virtual training environments for all of the classes that I teach.

I recently purchased a new Dell E6510 to travel around with. It has the i7 620M (Dual core, HyperThreaded cpu running at 2.66GHz) and 8 GB of memory. Reading the spec sheet, it sounded like it would be a great laptop to carry around and run virtual machines on.

Getting the laptop though, I've been pretty disappointed with the user experience of developing in a virtual machine. Giving the Virtual Machine 4 GB of memory, it was slow and I could type complete sentences and watch the VM "catchup".

My company has training laptops that we provide for our classes. They are Dell Precision M6400 Intel Core 2 Duo P8700 running at 2.54Ghz with 8 GB of memory and the experience on these laptops is night and day compared to the E6510. They are crisp and you are barely aware that you are running in a virtual environment.

Since the E6510 should be faster in all categories than the M6400, I couldn't understand why the new laptop was slower, so I did a component by component comparison and the only place where the E6510 is less performant than the M6400 is the graphics department. The M6400 is running a nVidia FX 2700m GPU and the E6510 is running a nVidia 3100M GPU. Looking at benchmarks of the two GPUs suggest that the FX 2700M is twice as fast as the 3100M.

http://www.notebookcheck.net/Mobile-Graphics-Cards-Benchmark-List.844.0.html

3100M = 111th (E6510)

FX 2700m = 47th (Precision M6400)

Radeon HD 5870 = 8th (Alienware)

The host OS is Windows 7 64bit as is the guest OS, running in Virtual Box 3.1.8 with Guest Additions installed on the guest. The IDE being used in the virtual environment is VS 2010 Premium.

So after that long setup, my question is:

Is the GPU significantly impacting the virtual machine's performance or are there other factors that I'm not looking at that I can use to boost the vm's performance? Do we now have to consider GPU performance when purchasing laptops where we expect to use virtualized development environments?

Thanks in advance.

Cheers, Dave

EDIT:

The HDDs in the two systems are 7200 RPM, the E6510 having 500GB vs. the M6400 have 2x 250GB in a non-RAID configuration.

Also, when I turn off some of the graphics features of Windows 7 (host and guest) by going to non-Aero themes, VM performance visibly increases.

Answer 1

I am running two VMs on my development system simultaneously, one for development, and one for TeamCity. My graphics card on my Dell Optiplex is an ATI 2450, which is, quite honestly, complete crap. Personally, I have found RAM and CPU to make the most significant impact on my desktop. But since you are on a laptop, have you thought about the disk? Our M6400 has an SSD, and perhaps that is the biggest difference for your two laptops. I would not expect GPU to affect anything, unless of course you are trying to use the experimental Direct3D features in VirtualBox.

Answer 2

A GPU can significantly impact performance of any system. Visual Studio, for example, has a huge performance difference between on board video vs dedicated graphics.

That said, I would expect there are other differences. First, how do the two hard drives compare? notebook manufacturers love putting slow disks in machines in order to beef up their battery longevity numbers; and other the other side, sometimes they put in the faster drives to boost performance numbers. It really depends on what the new machine was marketed towards. Along these lines some hard drives also have configuration settings to determine their power / performance / noise levels. Depending on the drive you might be able to tweak this.

Another expected difference is the quality of memory. Nearly every dell I've used has had second or third tier ram installed. Sure they might both be DDR3 of a certain Ghz, but the quality of the chips is going to determine how they really perform. Sometimes by 200% of more.

Beyond those you start getting into chipset differences, mainly in the hard drive controllers. You can't do anything about this though.

The next thing I can think of is drivers. Make sure your up to date on everything you can. Also, test both Dell and nvidia supplied drivers. Sometimes nvidia has better drivers, sometimes the original ones from dell are better. That part is a crap shoot.

And, finally, consider blowing away the new machine and doing a complete reinstall from the bare metal up. Before installing any anti-virus or CPU sucking software, test your VM performace.

Answer 3

Just to closer off this question with my findings, what we have discovered was that driver performance was limiting the perceived performance of that virtual machine. With the default Dell drivers, which are built for "stabilty" the virtual machines would be visibly impacted in "visual" applications like IDEs (Visual Studio 2010) such that VS 2010 could not keep up with my typing. When we had some nVidia reference drivers installed, the IDEs were crisp and you couldn't really tell that you were in a VM anymore, which was my experience with the M6400s.

Thanks to everyone who threw out some ideas on the subject.