# Citrix Servers Histogram

> Get an overview of your Citrix servers by CPU usage and number of active sessions.

Source: https://docs.capaone.com/performanceguard/i-want-to-know/i-want-to-know-if-citrix-works-ok/citrix-servers-histogram/  
Product: PerformanceGuard — a separate CapaSystems product; do not apply this page to any other.

The Citrix Servers histogram (**ANALYZE > Citrix > Histograms > Servers**) gives you an overview of all your [Citrix Performance Measurement](/performanceguard/i-want-to-know/i-want-to-know-if-citrix-works-ok/citrix-performance-measurement/) servers, or a group of Citrix servers, with respect to things like CPU usage and number of active sessions.

1. Select required **Citrix server**.
2. In the **Primary Type** menu, select the data set that you want to cover in the graph.

   - **CPU Usage, 90th Percentile:** Calculates the CPU usage in the busiest 10% of the time.

:::note[Important]
**Example:** If you are looking at a period of 24 hours, the CPU usage is at least this value in 2.4 hours of the period.
:::
   - **Free Memory, 10th Percentile:** Calculates the amount of free memory in the busiest 10% of the time.

:::note[Important]
**Example:** If you are looking at a period of 24 hours, the available memory is at most this value in 2.4 hours of the period.
:::
3. The histogram will include a top-x list of servers. For example, if you selected CPU Usage in the previous step, the histogram will include a list of the servers that used the most CPU. In the **Top X** field, select how many servers you want such a list to cover, for example a top 10 list.
4. Select the required **Interval** (that is the period of time that you want to cover). If the predefined intervals don't suit you, select **Custom** to [Custom Time Periods on Graphs](/performanceguard/analyze/custom-time-periods-on-graphs/).
5. Click the **Update** button.