This seems to be a long running issue for me as I've seen this on a few laptops in my time.

Current system:
Ubuntu 16.04 LTS 64-bit
MacBook Pro - 2.9 Ghz Intel Core i7-3520M IvyBridge
Intel HD-4000 Graphics
8GB RAM

My issue deals with 3D game performance.

For this post I'll use 0AD as a reference.

When I first launch the game, performance is quite good considering the Intel HD-4000 I'm using. Watching htop shows all 2 cores (4 threads) running as expected, mostly green (user) and game performance is smooth.

After a bit (1 minute? 2 minutes?) game performance gets really choppy and when I check htop, all 4 threads are mostly red! This will last for another minute or so and then, boom, game performance goes back to normal (good) and htop shows green for threads again and the cycle repeats itself. The game runs great for a few minutes and all green, then gets choppy while htop shows red threads again. It's like something is getting bottled up and then flushes itself.

This will happen on all games I play so I doubt that it's game related. Searching on the internet I have found no one else complaining about this. Maybe my searches are not spot on but I don't know what else to search for and since I have experienced this on a few laptops with Intel GPUs, I find it odd that no one else has had this issue. I would post screenshots of htop but that is not allowed here.

Can someone help me troubleshoot this issue?

Sincerely,

Certainly sounds RAM related. Graphics cards as of late will have some on-board ram, but if more is required they will use system ram also. This sounds like integrated graphics which only uses system ram. Perhaps not enough, perhaps one stick not performing properly, weak compared to the other, faulty or low quality.

I have a camera with a small cache, with run of the mill sd cards, I cannot do high res HD video for long because the write speed of the sd cards is not fast enough. Paying the price for top of the line memory works.