What does the split look like? I think there can be two answers here depending on the split...
If you train each bodypart twice per week, you can not train to absolute failure and expect to recover in time for the next workout and continue making gains, you will overtrain. If its once per week, then training to failure would be the way to go, knowing you have adequate time to recover from the high level of damage you have done.
Now if its twice per week with NOT going to failure (depending on the level of failure, are u talking 2max sets to failure or a whole failure workout?) you will be able to recover much faster while still stimulating growth, but you will have 2 growth phases per week instead of one, so i think that would amount to more gains.