Default [Q] Change maximum kernel frequency?

So I have this old tablet called the Portal by Magent. Basically, a cheap tablet I won about a year ago. Since I have a Nexus 7 2013 I thought I could toy around with this tablet and do some overclocking. The problem is, this tablet has no recovery mode and it can't get one installed. It is rooted though. So I was wondering if I could change the maximum kernel frequency without flashing a new kernel. I'm limited at 1.2ghz currently, but I'm aiming to get at least 1.5ghz. Got any ideas?