For daily driver duty a 50/50 mix is good. For more extreme temps on the cold side, you can go higher to 60/40, favoring the antifreeze additive.
But remember, water is your best or at least most efficient medium for cooling, and if you did not have a freezing problem and ran your car hard, something closer to 80% de-ionized distilled water,20% coolant and a bottle of Water Wetter would work even better for cooling. (The effects of Water Wetter are reportedly diminished by coolant/antifreeze). Since water and Water Wetter do not have the anti corrosion compounds in your antifreeze/coolant, it is not wise to run 100% straight water and Water Wetter unless you are racing and prepared to drain and refill the system with a water/coolant mixture with some frequency. And of course if the temps drop and your system freezes with water, the damage will be severe. Since draining, refilling and "burping" the system is a bother, this is typically a seasonal thing for a car that makes multiple performance visits to the track, or does some hard running in very high ambient temp summer locales.
For a hard racing motor, particularly something wrestling with heat gains associated with forced induction loads, and especially for high boost turbochargers which are "heat monsters", you can look into a more exotic, zero pressure, glycol based product, like Evans Waterless Coolant. Wierd stuff, but it works. Not for a ar used as a daily driver though. And probably not until other approaches to thermal management have been employed and there are still remaining issues with keeping the temps down. Those would typically include larger multicore aluminum radiators, fans, increased oil capacity (oil not only lubricates, but it it is part of the heat exchange process), synthetic oils better ableto handle heat, oil cooler, engine bay venting, increased oil filtration capability to remove more particulates (like down from the typical 30 microns to 1 micron or less with an Amsoil dual bypass unit-particulates attract and retain heat, thus increasing the overall temp of the oil they are suspended in...getting them out helps to reduce heat), thermal barrier and thermal dispersal coatings on key parts,etc etc.