Set proper Sample Rate for Site Speed http://blog.mythly.com/improve-site-speed-in-google-analytics/ Note: Google will automatically cap the sample rate to 10k pageviews a day.

google-analytics-siteSpeedSampleRate.js

_gaq.push(['_setSiteSpeedSampleRate', 100]);

google-universal-analytics-siteSpeedSampleRate.js

ga('create', 'UA-XXXXXX-Y', {'cookieDomain': 'example.com', 'siteSpeedSampleRate': 100});

Monthly Visits	_setSiteSpeedSampleRate Value (%)
1-10,000	100
10,001-20,000	50
20,001-50,000	25
50,001-100,000	10
100,001-250,000	5
250,001-500,000	3
500,001-999,999	2
1,000,000+	Don’t override the default

monthly visits meaning page views or sessions?

I assume this would be sessions not page views?

Visits is the same thing as a session.

It seems GA also does also sample timing hits on their servers: https://developers.google.com/analytics/devguides/collection/analyticsjs/user-timings#sampling_considerations

Did you take that into consideration as well?

Hey. What is this part used for:
'cookieDomain': 'example.com', ?
My analytics.js is hardcoded (not GTM), should I replace the:

<script> . . . . ga('create', 'UA-XXXXXXXX-2', 'auto'); <---- replace this? how? ga('send', 'pageview'); </script>