Is it normal on the ISR 4351 with this free memory using the show platform software status control-processor brief command? No initial configuration on the device and also out-of-the-box.
Looks like there is some configuration on as the hostname has been changed?
Suggest wr erase the rtr and reload the box, Also check the flash and see if there are any unnecessary files that could be removed.
Lastly check the ios version for any identified known bugs to it.
Even if this has been configured with a hostname , the free memory does show 1% at all? The router is not yet on production.
What you said was the rtr was out of the box hence my statement about it has a hostname, meaning it must have had to changes made to it, hence the suggestion to wipe it.
sh processes memory sorted - will show you the memory utilization of the rtr