From the Server Perspective

Given that Microsoft makes Outlook, one would expect that Outlook works well with Microsoft Exchange servers. It was beyond the scope of this project to benchmark servers, but we wanted to see how different mail applications behaved from a “server” perspective. This is of particular interest to Enterprise and IT system administrators given they need to look at performance for the entire organization, as well as, the servers.

Below are four samples — screen shots of the CPU usage graphs on our test on premise Exchange 2013 server.

The first screen shot (figure 15) shows a baseline of the server — what it looks like when no clients are working syncing mail. Its “idle” state, if you will. The green line represents the CPU usage. The blue line is the “maximum frequency” which is essentially how fast the CPU is running (faster also means greater electricity usage).

The second, third and fourth samples show Mail.app, Outlook 2011, and Outlook 2016 each syncing an Exchange account, respectively.

As you can see, Mail.app (figure 16) does not consider it important to “be kind” to the Exchange server. It’s pretty clear here that Apple is not respecting the guidelines for mail clients talking to an Exchange server. They are breaking the rules (at least in how Microsoft Exchange is expecting a client to behave). Note the spike to 60% CPU usage — something we saw often.

Outlook 2011 does fairly well and is relatively even handed (figure 17), frequently hovering around 10% CPU usage.

Clearly, Outlook 2016 is the most respectful, and “kindest” to the Exchange server (figure 18). Outlook 2016 was so good to the Exchange server, that it often used only slightly more than the equivalent of an “idle” server.

15-ExchServer-Baseline

Figure 15: Exchange Server CPU Usage – Baseline
(Green is CPU Usage, Blue is Maximum Frequency)

16-ExchServer-AppleMail

Figure 16: Exchange Server CPU Usage – Mail.app
(Green is CPU Usage, Blue is Maximum Frequency)

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Figure 17: Exchange Server CPU Usage – Outlook 2011
(Green is CPU Usage, Blue is Maximum Frequency)

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Figure 18: Exchange Server CPU Usage – Outlook 2016
(Green is CPU Usage, Blue is Maximum Frequency)