i found this, and this is the truth:
did some testing.
_My symptoms_ were as follows:
1. Graphic artifacts during light gaming
2. Random screen (system) lockups while gaming (hard reset needed then)
3. Spontaneous restarts when gaming
4. The above led to lines on screen (app windows) after I quit the game. Lines were exactly like those shown in post 1 of this thread. I only got the lines, no color gradients on screen.
_So what's going on?_
Various reasons can cause this behavior, but after testing with some fancy utilities I pretty much established the cause - *it's bad soldering of video memory chips*. Declocking the VRAM does not help, which means it's not VRAM overheating or chips failure.
It's BGA soldering points failing in Radeon X1600's VRAM chips. There are 8 of them on the logic board in my case (128MB VRAM).
Not surprisingly this happens more frequently at higher temperatures, or when the chips are 'stressed'. It may be also connected with heat cycling (running hot/cold/hot/cold, then it starts to fail mainly when it's hot).
So it's really not an overheating issue per se. In my case the GPU never exceeded 65* Celsius - this is OK according to spec.
I also noticed that in my case if the GPU stays below ~54-58 deg Celsius, nothing really happens.
But let it work a little while at ~60-65* Celsius and graphics will fail imminently.
What one can do about it?
This could be the solution:
1. REBALLING of ALL video memory chips. This means changing all the soldering points (connections between the memory chips and the logic board) to new ones. This can be done in a specialized service point (non apple) and should cost about 100 bucks at most.
2. REFLOWING of ALL video memory chips. It might also work and should be way cheaper, while it's also way easier to do. This basically means trying to fix soldering points that failed so far but doesn't really guarantee anything.
You do not need to replace the whole logic board.
If you're out of warranty and your problems with graphics are really, really, really bad, you can try point 1 or 2.
Otherwise I suggest you try the following.
Workaround:
While not eliminating the cause +at all+, in my case the following *eliminated all the symptoms*.
Not all of the following is necessary but I'd recommend you do it to help your chances:
1. Total disassemble of the logic board, replace thermal compound on the CPU, the GPU and the logic board Chipset. . This will help keep them cool - which will help keep the video memory chips cool also. Take a peek at ifixit.com
2. Use CoolBook to undervolt your CPU. I know a lot of people hate this tool. +But it really increases your chances here.+ It is a tricky game so be careful. While it's not a free tool, it's really worth a go. It simply allows to keep the CPU very, very significantly cooler when undervolted (it can still run at max performance of course, that's the point). Remember, CPU's heat effects all the logic board and airflow inside the Macbook, so it also warms the GPU and the VRAM chips this way.
3. Of course, finally use smcFanControl or Fan Control to keep your fans running at higher speeds then normal, without hurting your ears. Ideally you should get below 50* Cel. on GPU when idle and max 54* when gaming. In my case this means running at around 3900rpm when idle and 4900rpm when gaming.
I use CoolBook, +Fan Control prefPane+, and have also replaced the thermal paste (a while back when I had a chance). My Core Duo 2.0GHz now runs at 48-50* Celsius idle, with GPU at 46-48* Cel when idle.
This is *a lot less than stock temperatures* of MBP1.1 and *in my case I got completely rid of all the symptoms*.
Sounds not that bad now, does it?
There's a downside though.
I've been using CoolBook and smcFanControl/Fan Control for a long time. Now I just increased the fan speed really.
This means my CPU/GPU/VRAM/Chipset were working in a way cooler Macbook Pro then in someone else's case.
What I mean is that in your case if your Macbook has been working frequently with stock fan and voltage settings (so CPU at ~85-90* Celsius), the logic board components (and solder points) might have gotten damaged/stressed way beyond expectations. This means that in some cases the logic board replacement might indeed be needed now.
If in your case the problems also appear when the GPU runs above around 55* Celsius, then my advice is:
If you're out of warranty and don't feel safe about reballing/reflowing, and if you're also screwdriver-literate, go for the workaround I mentioned above.
It's a bit of work but should pay off. No warranty though, good luck.
In case you have questions mail me at gplayerallegro at gmail , com .
i have to tell you that i'm running fine 10.7.2 but when cpu is fully load and reaches 60-65°, my system freezes. so i didn't find any solution, neither reflowing it (i tried 3 times)
system freezes even with coolbook, undervolting cpu with settings that i found on internet for my machine (mbp 2,2; 2.33ghz;x1600 256mb)
