Ethereum mining: DAG file grows, RX series hashrate decreasing

Growing DAG file equals more stressed GPU
So I noticed something by waking up this morning and seeing that my hashrate of my RX series GPU has decreased a tiny bit.
The same might have happened to you guys, so here is a explanation and what to expect as the DAG keeps growing.

How fast does the DAG file grow?
The DAG file grows every 30.000 block of Ethereum mined. Which is estimated by many mining pools to be around 5-4 days.

Yesterday Ethereum went on to DAG epoch 130, but what will happen with the hashrate in the near future?
I have done some benchmarks with my own RX 470 4GB and my RX 570 4GB.

So I went onto TeamViewer, fired up Claymore miner and wanted to test out my hashrate after 10 and 20 DAG epoches, 140 and 160.

In my .bat file i add the command:
-benchmark {DAG-file}

Before DAG 130 (Benchmarked at DAG 129)
Sapphire Nitro+ RX 470 4GB (Modded BIOS: 28 MH/s)

MSI Gaming X RX 570 4 GB (Modded BIOS: 28 MH/s)

After DAG 140
Sapphire Nitro+ RX 470 4GB (Modded BIOS: 28 MH/s)

MSI Gaming X RX 570 4 GB (Modded BIOS: 28 MH/s)

After DAG 160
Sapphire Nitro+ RX470 4GB (Modded BIOS: 28 MH/s)

MSI Gaming X RX 570 4 GB (Modded BIOS: 28 MH/s)

DAG 140: In about 50 days~~
DAG 160: In about 150 days~~
Don't hang me up on this calculation.

As of now, I haven't got any benchmarks from the 8 GB models, but I'm more than 100% sure, that they are affected by this aswell, but more lightly, as they can handle more stress, than the 4 GB models.

As a conclusion, in the nearest future we will see drops in our hashrate for every new DAG epoch. I would personally keep on mining Ethereum untill it isn't the most profitable coin anymore. Cryptocurrencies that doesn't include the Ethash DAG growing epoches would not affect the RX series hashrate - ZCash, Expanse and Monero as an example.

Who knows if the switch to PoS would change this RX problem.