# Changing the clock frequency **URL:** \ **Category:** HiFive1 Rev B\ **Created:** [May 26, 2017, 10:01am UTC](https://forums.sifive.com/t/changing-the-clock-frequency/570 "2017-05-26T10:01:34Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![jkilbride](https://avatars.discourse-cdn.com/v4/letter/j/5e9695/32.png) [@jkilbride](https://forums.sifive.com/u/jkilbride)\ **Post date:** [May 26, 2017, 10:01am UTC](https://forums.sifive.com/t/changing-the-clock-frequency/570/1 "2017-05-26T10:01:34Z")
Hi, Sorry, I am new to all this so please excuse any stupid questions. I am up and running with the standard dhrystone example code from Github. Is there any way I can vary the clock frequency so i can see how my results vary as I change the clock freq? I realise that the calculation is score/MHz so it shouldnt really matter, but this thought this would be an easy way for a h/w guy to gain some programming/makefile skills! ---
**Author:** ![dgrubb](https://sea2.discourse-cdn.com/flex020/user_avatar/forums.sifive.com/dgrubb/32/23_2.png) [@dgrubb](https://forums.sifive.com/u/dgrubb)\ **Post date:** [May 26, 2017, 12:23pm UTC](https://forums.sifive.com/t/changing-the-clock-frequency/570/2 "2017-05-26T12:23:01Z")
Be sure to read [Chapter 4 of the E300 platform reference manual](https://www.sifive.com/documentation/freedom-soc/freedom-e300-platform-reference-manual/) as there are a few different ways to experiment with this. There’s also an applied, and well-commented, [example in init.c](https://github.com/sifive/freedom-e-sdk/blob/master/bsp/env/freedom-e300-hifive1/init.c) which demonstrates how to set oscillator sources and set the PLL. Have fun! ---
**Author:** ![jkilbride](https://avatars.discourse-cdn.com/v4/letter/j/5e9695/32.png) [@jkilbride](https://forums.sifive.com/u/jkilbride)\ **Post date:** [May 26, 2017, 2:05pm UTC](https://forums.sifive.com/t/changing-the-clock-frequency/570/3 "2017-05-26T14:05:52Z")
Ahh, makes sense, thank you