The DC-DC intelligent transformers are able to compensate for the voltage drop and keep the computer online when cranking the starter. I don't know the specific technical details but I think the general technology is referred to as a switching transformer. The voltage is actually switched to AC, stepped up to a sufficient AC voltage, then reconverted to DC at the proper voltage. If the DC voltage drops, the transformer is able to compensate unless it drops quite low.
However, their ability to do so is dependent upon the quality of your installation. You need to ensure that your power cables are well connected, your ground wires are well connected, the wire gauges are sufficient and so forth.
You may not have seen people complain about it, but there are a fair number of posts about computers not surviving crank from forum members.