More reasons VDI costs less than PCs

Posted by Tom Rose on Apr 9, 2015

We've been getting a lot of feedback on our blog VDI Cheaper Than PCs. Several people have raised some good points and asked for additional information about the customer's choices.

One question was how replacing PCs with thin clients would impact the cost comparison, and whether Microsoft VDA would also be a factor. I'll try to answer that question here.


Q: A big argument for VDI is getting rid of old hardware, so at some point you’ve got to factor in thin clients replacing the PCs. How does the model account for that?

A: The customer decided to repurpose PCs that were already covered under Microsoft Software Assurance (SA), so there were no additional endpoint costs up front. But they acknowledged that as these PCs reached end-of-life, they would likely be replaced with thin clients.

At that point, you will have 2 additional costs to consider:

  1. Microsoft Virtual Desktop Access (VDA) subscription, which runs about $100 per user per year and covers access to virtual desktops from non-Windows devices (like thin clients).
  2. Cost of new thin/zero clients, which typically run $200-400 each.

However, these 2 new costs will be offset by 2 new cost savings:

  1. Energy savings. Thin/zero clients use as little as 4 watts of power per hour, compared to PCs which use between 60 and 100 watts per hour. As Unidesk partner Dell explains in its Dell Wyse EarthSmart Computing page, "6.6 watts of electricity is the equivalent of a single C7 light bulb on a Christmas tree. One such Wyse customer, a Fortune 100 retailer, saves more than five million dollars per year on energy costs alone." Even factoring in the additional power needed by servers to host the virtual desktops, your electric bills will be significantly lower with zero clients.
  2. Longer lifespans. As long as you invest in thin/zero clients that have high-performance chips and high-end graphics processors, you should get several more years of use out of them compared to PCs that have only 3-5 years of useful life.

Taking this next step also gets you the added benefit of mobility and BYOD. Once you've subscribed to Microsoft VDA, which is now per user and not per device (see "Without screwing us in a new way, Microsoft fixed VDA!" on, users will be able to access their virtual desktops from any endpoint device.

The (Updated) Bottom Line

Here's what happens when you calculate the new costs:

  • Microsoft VDA (1 year, 200 users): $20,000
  • New zero clients ($300 per device, 200 units): $60,000

Now calculate the energy savings. We assume new zero clients use 4 watts per hour 8 hours per day; old PCs use 80 watts per hour 8 hours per day; 2 new servers to host virtual desktops use 460 watts per hour and are always running; and electricity cost per kWh is the US national average of $.12:

  • Energy saved by VDI over PCs (1 year): $2,390

The last consideration is that you'll need to buy new PCs again before you have to replace your zero clients. To account for this, you have to look at the 5 year horizon.

PC refresh first:

  • PC refresh cost (5 years): $190,000 x 2 = $380,000.
Now VDI:
  • VDI CapEx (from VDI Cheaper Than PCs): $137,200.
  • Zero clients: $60,000.
  • Microsoft VDA (5 years): $100,000.
  • Energy savings (5 years): ($11,950).
  • VDI Cost (5 years): $285,200

The bottom line is VDI costs considerably less than PCs even buying new zero clients and gaining the benefits of BYOD and anywhere, anytime access to Windows desktops and applications.

And that's without factoring in the operational cost savings of Unidesk layering innovation.

What do you think now that we've added in these new variables? Keep the feedback coming!

Topics: BYOD, Cost

Posted by Tom Rose on Apr 9, 2015

Request a Unidesk Impact