Performance impact of Office 2007 on Citrix servers

The Office suite plays a major part in Citrix farms. Not only is it probably the most distributed application suite around, it is also the most used and one of the most resource intensive set of applications on Citrix farms. Maintaining a stable and well performing Citrix farm is probably the greatest concern for every Citrix administrator, so the introduction of a new version of the Office suite will make those eye browses frown of the common Citrix administrator.

Microsoft introduced late 2006 a new Office suite, called Office 2007. Earlier releases of the Office suite always had a significant negative impact on the maximum number of users that were allowed to get access to a Citrix server. So the obvious question to ask is: What is the impact of Office 2007 on a Citrix server compared to Office 2003?. Are we again facing a considerable performance penalty and, if so, how large is this penalty and which specific resources are impacted?

The test

To answer this question we set up a test server (a Dell 1850, 2 (hyperthreated) Intel Xeon 3.2 Ghz with 4 GB of memory) and used the Citrix Server Test Kit to run a number of simple scripts against Office 2003 Standard Edition SP1 and Office 2007 Enterprise Edition.

To be more specific we started 30 user sessions (one session per 2 minutes) and each session did the following:
1. Log on to a Citrix server
2. Start Outlook
3. Start Word
4. Start Excel and perform a number of simple calculations
5. Start Powerpoint, insert a number of slides, type some sentences
6. Wait for 5 minutes and start from step 2 again

We acknowledge the fact that those actions cannot be compared to actual user behavior. However, it does give a quite a good picture of what the performance impact will be.

After some time we logged of 5 sessions, because those 30 sessions already used all the CPU available when using Office 2007. Then we let it run for some time more.

The Result

Now  without further let’s bring in those Resource Manager graphs. The 4 most important ones are right here:

On average some 40 %.

The same graph, but now for Office 2007:

We see an average of 70 %.

Let’s take a look on the processor queue length for Office 2003:

It almost drops down to zero.

The same graph for Office 2007:

Still quite significant!

So what we see from this small test is that Office 2007 consumes way more CPU. If we do a small math:

40% (average 2003 CPU) “ 10% (normal OS CPU) = 30%
70% (average 2007 CPU) “ 10% (normal OS CPU) = 60%

That would make twice as much CPU for Office 2007!

We also checked memory and context switches. Memory consumption was very much the same between the two versions, but context switches was a different story:

Office 2003:

On average 35.000.

Office 2007:

On average 20.000 and more stable. So this shows an opposite result compared to the CPU charts. This time the results are in favor of Office 2007.

The conclusion

Overall this table summarizes the results:

Resource Impact of 2007 compared to 2003
CPU + 100 %
Memory Same
Context switches – 40 %

So what does this mean? It means that for those environments where CPU is the bottleneck the implementation of Office 2007 will definitely mean that you will have fewer users on your existing Citrix servers. How many less? That depends on things like:
• What is the real user behavior? Remember the scripts only perform very basic user actions. Real user behavior may well be different. According to Microsoft Excel 2007 makes more efficient use of the resources available for heavy calculations and those calculations may be finished quicker. So if your users use Excel a lot, the results may differ.
• How many other applications do you make available on your Citrix server? The relative impact of the implementation of 2007 will be less if your users mainly work with other applications.

Here is graph of company that has approximately 80 applications on a Citrix server:

For this customer the CPU consumption of the Office applications combined is more than half of the total CPU demand. Introducing Office 2007 on such a server will decrease the maximum number with a third.

So what if memory is your bottleneck? Will everything be all right then? Only if memory is still your bottleneck after the implementation of Office 2007 and not your CPU. You can easily recognize when CPU is likely to be a bottleneck. Just check your % Processor Time and Processor Queue Length and if it is similar to the graphs below you’re reaching the max of your CPU:

So Office 2007 has a significant impact on the CPU. Will that make SBC as a solution less attractive? Not at all, basically it is IT as we know it. Because together with the higher resource demands we also have higher resources available. 2 years ago a 2 CPU server was the standard, nowadays a 2 duo-core CPU is the standard. What it does mean is that companies should budget for server upgrades just like they do for workstations. Furthermore we have to switch to x64 bit operating systems eventually.

By the way, Office 2007 is at this moment not supported by Citrix!. This link shows the current issues they are having and they intend to have those fixed by mid 2007!

So the information given above combined with your own Resource Manager statistics will make it possible for you to do a decent guess on what to expect when you implement Office 2007. Once you have decided on implementing Office 2007, you probably want to know how to implement 2007. Office 2007 deployment has been revised and there are conversion issues to solve. I will blog on these matters within a few weeks, so keep an eye on this website!

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