Minecraft is going So laggy?

I have tried EVERYTHING. Optifine, clearing RAM, messing around with the instillation of Java etc. Deleted a BUNCH of files to see if it would help but nothing. I've made sure I only have one version of Java (64 bit) I'm on a Packard bell notebook but it shouldnt be a problem because I play other games with a high graphic demand and it runs perfectly. But minecraft just lags and lags and lags All the time. It jumps from 40fps down to 3 then back up and down again its so annoying. I've tried mods video settings, everything! Is there anything else i can try? Thank you in advance

Added (1). Diablo*
RAM: 4GB
Total physical memory: 3.93GB
available physical memory: 1.17GB
Total visual memory: 7.86GB
Available visual memory 3.50GB
Page file space: 3.93GB
Is that enough?

First off, you should right your complete computer specs! Then I will try answer your question

Minecraft is CPU-intensive java app. It'll lag if your rig are sporting an outdated processor.