The daemon uses around 1 GB on my seed node. It hasn't been able to run on 512MB for a while now.
This appears normal for almost 5 million blocks in the chain. This is similar to other coins that has 2+ years of blockchain data.
I have other coin in pool that are very old, but it was running in the same server without memory problem.
The problem, for me, it that after downloading less that 5% of blockchains, it uses more that 1GB in increasing rate!
I can understand that with 100% blockchains it could take near 1GB, but not with 5% downloaded.