Opencart use too much memory

Hi guys,
I just moved my site to a VPS with 484MB-512MB memory. 1st month, the opencart and website is running good, however, now, in the 2nd month, the website is deadly slow and VPS report out of memory, it is nearly down.
I tried reboot the VPS and it can not fixed the problem. I did not change anything since I moved to VPS, why opencart just took so much memory now?
Thanks.

That is not much memory for a store. The situation is worse if you are using Cpanel or Plesk, either of which will use about 1/3 to 1/2 the memory you have. Also, you could be running Spam Assassin a Mail Server, a FTP server, and other things in addition to MySQL which is required by Open Cart. Further, you could have a store with ten thousand products.

I suggest you talk to the provider of your VPS about the memory usage and discuss what you need or don't need running. You need the mail server, you don't need the FTP server all the time.

Hi,

Just came back for the feedback. I found the sql query out of memory in error log, my opencart is 1.5.1.3. So, I updated the Opencart to 1.5.3.1, now, it looks that website is normal ,and memory usage is normal as well.
I will keep monitoring the memory usage until I ensure website is working fine.
Thanks.