On leases of 12 months or longer, you get full BIOS access through remote KVM. You can tune memory timings, adjust power limits, change core ratios, or run the machine outside stock settings if your workload calls for it. It’s your box for the term of the lease, so you can set it up the way you want.
We don’t usually recommend this however, as stock settings are stable. But if you know what you’re doing and have a specific reason, the access is there.