I modded my MSI 6600GT AGP

Question

           I took my MSI 6600GT AGP all apart to mod it. I thought I would share what I found out in case anything wants to mod theirs also.
I didn't want to flash the bios for the temperature, so I attached this probe to the GPU.
http://www.bestbyteinc.com/prodinfo.asp?number=SEN-CNU-001
The bridge chip uses a thin foil thermal pad, which I replaced with Artic Silver Ceramique. The GPU heatsink uses what I think is a thick thermal compound, it didin't come off like a pad. It might also have some silver content because of it's grayish color. There are four approx. 1/16" white thermal pads for the memory.
I don't think both of the heatsinks are copper. Because when I removed the heatsink I could see in the threads of where the support arms get screwed into and it wasn't the same color as copper. I think they are copper colored anodized aluminum or maybe even copper covered aluminum if that is even possible. My best guess is they are not copper. The color is slightly wrong to be true copper.
To take the main heatsink off.
You need to press down slightly on one side of the back support bar and swing if off of the post. If you look at the support bar both ends are different. One side has little metal nubs that need to clear the post to swing it off. The other end is shaped like a C and just rides on the groove in the other post.
After you take off that bar, there is another flat bar that has a pad in the middle to protect the components. That bar just lifts straight up and off the posts. Remember which way you took it off, it is very important. The components make litte dents in the pad. So putting it back on the exact same way fits the components in the same dents they made when the bar was first installed.
Once you have both support bars removed, you need a flat screwdriver to unscrew both posts from the heatsink. At this point I don't believe the heatink is attached anymore to the board even with the posts still attached. Once you take off the posts flip the card over holding the heatsink as you do so. I gently twisted the heatsink and it came right off. You need to unplug the fan at this point.
I took four copper slugs around the size of a penny, and thinned them down to get the right height of the pads. The pads were removed to be replaced by the copper slugs. It took a very long time to do this. I would take one and rest it on the memory. Then I would use a small straight edge ruler to test the height with the GPU. The copper slugs have to be at the same exact height or slightly lower then the GPU or the heatsink will not make proper contact with the GPU.
What I found by doing this is, without having the support bar on the video card the GPU is not on a flat plane to the memory chips. So thinning the slugs down the right height was hard to do because of this.
Once I got the slugs down to the right height I used Arctic Silver thermal epoxy to glue each one to the memory. After that I used the Artic Silver Ceramique on the GPU and on the copper slugs. Then I attached the thermal probe with a little dab of Artic Silver Ceramique on the tip to contact the side of the GPU. I used double sided thermal tape to stick the probe to the board and to the area on the side of the GPU.
I then re-attached the heatsink in the reverse order I removed it. I checked under the heatsink with a light and everything looked like it was making good contact.
My idle temp with the probe is around 34C, stressing the card with benchmarks the highest I have seen it is around 55C.
The copper slugs didn't really gain me all that much overclocking the memory, but that could just be the memory has reached its limits. The copper slugs will probably help the memory last a little longer then the pads. I wouldn't suggest using the slugs to anyone. It is just too much work, a lot of risk and doesn't really gain you anything. 

Answer 1

Quote from: akeer on 16-February-05, 18:17:49
fw off, agp set to 4x.... many times tried this with various drivers (also setting the 2d and 3d speed to the same and many other trix...)
also tried to unplug devices... no help.... as I said if I help the cooling with really biiiiiiig fan underneath the card, it will not freeze... but 12cm fan at full speed generates looooooots of noise ))
it seems that aftermarket cooling (e.g. Zalman vf700cu) is the only solution
thanx and have a nice day
Here is something I just thought of. There are a lot of components on the board. There might a possibility one of them is not working very well when it heats up.
The GPU could also be overheating, but you have to understand something here.
The 6600GT has automatic core slowdown if it gets too hot so how could you have damaaged it? If you didn't put on enough thermal compound or the heatsink wasn't tight enough the core would slowdown to protect itself from heat damage.
If it was damaged by heat going by everything I know so far, it would probably only be damaged in the first few seconds right after you turn the computer on, but even then that would probably only happen if there was no heatsink attached at all.
Another thing to consider. I have an idle temperature of around 34C using the probe, the internal temperature would be slightly higher so lets say it's around 40C. The highest load temperature I have seen has been around 55C with the probe, so lets say inside its around 60C inside.
Those temperatures using the stock heatsink are very good.  So what I am saying is even if you get a new heatsink, it might lower the temperature a bit on the card...but I doubt it will help with any heat related problems your describing.
If that stock "heatsink is on correctly" it should be more then enough to keep the card cool.
Maybe you should take the chance and flash the bios so you can see the actual internal temperature of the card. At this point it really doesn't matter because you can't return it anyway, but there is always a slight risk flashing a bios.
There is a forum here that will explain flashing the bios if you decide to do it.
http://www.mvktech.net