You can still mine with 4GB cards with a special miner software called lolminer. It has a method to somehow mine even if the DAG is larger than 4GB. Sounds amazing doesn’t it? Yes but there are a few issues.
One of them is that every new DAG the speed slows down by a large margin while consumption remains the same. The first DAG where Phoenix miner stopped working for me, I got 28.5mhs from my regular 29.5mhs. Now a few dags later and it’s down to 22mhs. Basically every dag it slows down by 1mhs or so. So good for maybe another month and then time to upgrade the GPUs.