Is it normal that...

[[Jordan]]

Afaik minecraft takes more memory as time goes, as do many other applications.
If the memory runs out, it will start using the HDD instead, which will go very slow.
On older computers it's a good idea to shutdown, pull the power cable and let it stand for 1-2 hours.
Doing that will free up on memory.

1. CTRL+ALT+DEL to bring up the task manager when your computer is lagging.
2. Find minecraft under Applications, right click it and choose "Go To Process".
3. Check how much memory it's using and report back here.
4. Check CPU Usage at bottom and report back here.
5. Which process is using the most CPU?
6. Press Performance tab, report the following values: "Total", "Cached", "Available" and "Free" under Physical Memory.

If RAM isn't the issue, it could be overheating, things do run slower on higher temperatures.

3. 569,000 K and rising
4. ~50% CPU Usage
5. differs between System Idle Process and javaw.exe
6. Total: 1046604, Availible: 40928, Cache: 65580 (approx)