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nightking

macrumors newbie
Original poster
Aug 6, 2010
6
0
Hello!

So I've bought a new ML and installed as a clean copy (MacBook Aluminium late 2008, 8GB DDR3), no update. And the OS is very fast, Launchpad works fine, in Lion there was a problem with choppy animations on my GPU but it is fixed in ML.

But there is another issue. For example if I'm playing Minecraft it works very well for a first 5 minutes but later... Horrible experience. FPS drops from 60 to 15-20. And after I close Minecraft app, animations in Launchpad are very choppy! It gets better, after few minutes. It looks like performance of GPU is worse when it's hot. I'm pretty sure that it is not depend on Minecraft because sometimes I can experience it by only using OS.

Do you 9400M users have the same issue? Is it possible to fix it?
 

coccoborg

macrumors newbie
Aug 1, 2012
7
0
It's overheating

Your MacBook is from 2008 and I assume you never cleaned the cooling system. Dust collects in the radiator and doesn't allow air to properly cool the heatsink down, thus leading to cpu and gpu overheating, prolonged overheating can damage the cpu and the gpu and dry the thermal paste, the system detects this issue and automatically slows the cpu and the gpu down to produce less heat.
To make sure you are having this problem, download and install smcfancontrol or any other similar program to monitor temps. When idling it should read something like 35-40°C and 70-80°C when under heavy load (eg: gaming) if the temps are significantly higher you Mac is overheating.
If you happen to have the overheating issue you then have to take apart your MacBook remove the fan and clean the dust off the heatsink, if this doesn't help, it means the thermal paste has dried and you need to remove the logicboard remove the heatsink and re-apply a new layer of thermal paste.
Cleaning your heatsink from dust once every 1-2 months will prevent damage to your computer and make it run at full speed :)
Hope this helps

(btw, I apologize for any grammar mistake, I'm Italian and still learning English;))
 

nightking

macrumors newbie
Original poster
Aug 6, 2010
6
0
Thanks for answer.

Well, my MacBook was cleaned few times, so dust can't be a cause, but I must check thermal paste because as you said it might be a problem, and I'm sure that thermal paste wasn't changed.

(no problem, I'm from Poland and I'm still learning english too ;)
 

Hakiroto

macrumors 6502a
Jul 8, 2011
641
221
Hi. I'm having the exact same problem. I bought my MacBook Pro in September 2009 and it also has the 9400M (as well as the 9600GT - both 256MB). I used to get around 70fps playing Minecraft but since installing a fresh Mountain Lion (on a brand new SSD) I've had performance problems. I always used to use OptiFine and run this using Magic Launcher. As I said, since installing ML I've noticed horrible performance issues in the game. I will be getting 50fps one minute then the next it's right down to 10-20fps. I heard my fans going crazy in the MacBook. As I recently installed the SSD I took the opportunity to quickly clean what dust I could see from the fans. To be fair, there wasn't much. Maybe it's possible to remove them completely and clean them properly.

Anyway, let me know if you have a solution to this issue.
 

coccoborg

macrumors newbie
Aug 1, 2012
7
0
thermal paste

Well, I would still recommend replacing the thermal paste :) but first, try using a program like smcfancontrol (free) to check what temperature your cpu is running at when playing games :)
 

coccoborg

macrumors newbie
Aug 1, 2012
7
0
Just installed Mountain Lion on my late 2009 Macbook (the white unibody one) and it works perfectly, I've tested the GPU in a couple of games (Galaxy on fire 2 and Flatout 2) and it works flawlessly.
 
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