Recently I was putting together a proposal for a customer who needed to refresh 40 desktops, in the proposal I needed to compare the costs of replacing the aging desktops with new HP Desktop PC’s versus replacing them with VMware View Desktops. This particular customer already has VMware and has the need to upgrade their SAN and cluster capacity for another project, so adding in a little more disk and a little more compute resources would not be an issue. Instead, they wanted to know what the true cost of licensing, hardware and other indirect costs were on both sides.
What I came up with was about a 30k dollar delta to go with virtual desktops instead of physical HP Desktops. Obviously, I want to push for virtual desktops because of the lower maintenance involved with maintaining the hardware, but I would still need to justify that extra $30k. The first thing that I used was power.
For 40 HP desktops, I figure they would pull about 200watts per desktop if those desktops run 24 hours a day for a month that is 733 hours. That is 146.6 kWh per desktop and I figured 10 cents per kWh as the cost for power, which makes each desktop cost about $14.60 per month to run. Multiply that by 40 desktops and we are at $586.40 to run our desktops every month.
Now let’s look at virtual desktops: I am suggesting the EVGA PD02 terminal which pulls on average 12watts (according to their documentation), I then multiplied it by 733 which gave me 8.79kWh per month and then I multiplied that by 40 terminals to get 351.6 kWh per month… for all 40 terminals!!! That is $35.16 to power them, I also added 200watts for the extra server that it would take to run the desktops which add $14.66 to the monthly cost… for a total of $49.82.
So overall going with terminals and View Desktops will save us $536.58 per month, or $6439 over 12 months… which works out to $19317 over 3 years!
What I’m getting at here is that the power savings alone will be enough to pay for 2/3rd’s of the upfront cost of VDI over 3 years. To finish justifying VDI… figure out the amount of time it takes to update one application on 40 PC’s…. then figure the amount of time it would take to update one template and refresh the desktop pool…. Over three years of application installs and upgrades It is quite clear that VDI will more than pay for itself!
Also, on a side note, I would expect that 10% of the terminals over 6 years would fail… But over 6 years I would expect to replace 75% of the PC’s…. so If you were to figure a 6 year replacement schedule VDI really shines as the true lower cost.
Also, check out my “Take 2” post on justifying VDI.