Confused. Question for those who have mounted RAMsinks on 6800GT with reference HSF

[babybunny]

I'm watercooling my 6800GT, which means I have to mount RAMsinks onto the 6800GT. I have a [L=MSI NX6800GT]http://www.msicomputer.com/product/p_spec.asp?model=NX6800GT-TD256&class=vga[/L]. It looks like it has the reference HSF.

Here's what happened:

1. Took off retail HSF, cleaned off remaining thermal compound with acetone.
NOTE: The thermal compound touching the RAM was a thick, pink, squishy material. It felt waxy to the touch. Definitely not sticky at all.

2. Put RAMsink on RAM. This is where it gets weird: The sinks would not adhere at all. They would actually SLIDE around on the RAM surface when moved lightly with a finger. Took off RAMsink, felt the bottom, and the thermal adhesive was definitely very very sticky.

3. Tried putting sink on a second time, this time applying pressure. Still the same thing.

4. Figured that the RAM surface was either oily or the adhesive is not strong enough.

5. Cleaned RAM surface with a bit of palmolive detergent (emulsifier). Replaced adhesive with a stickier kind.

6. Mounted sinks again. This time it is a little bit stronger, but can still be knocked off quite easily.

WTF is going on? Does anyone else have this trouble? Am I going to have to resort to a nonpermanent mixture of AS and thermal epoxy? What could be covering the RAM surface?

[ferdb]

The thermal pads they use between the stock heatsink and the ram chips has this oily adhesive thats tough to get off. You either have to clean the beejuzes out of it to stick on ramsinks or use mounting hardware to hold the sinks on. I have an Evga 6800GT which actually has seperate heatsinks for the GPU and the RAM. I removed the fan shroud and the GPU heatsink portion. I removed the stock RAM heatsink pads and cleaned them and the bottom of the RAM heatsink assembly (I used Goo Gone) then remounted the RAM heatsink after putting AS3 on the RAMs. Mounted my MCW50 water block with the hoses running toward the front of the computer so as to not block the airflow. My case runs negative pressure with all the fans sucking out so to get good airflow across the card I left the next card slot open in the back of the case (put a piece of mesh over it to reduce dust intake). I then mounted my sound card in the slot after that and taped a piece of paper from the top of the 6800GT card over to the sound card forming a cooling tunnel for the air from the empty slot between the two cards to flow over the vid card ram sinks. The arrangement cools the RAM quite effectively. You may need to tape up holes in your case where air comes in that doesn't cool anything effectively (like empty drive bays), this will increase the airflow being sucked in over the vid card. All depends on your case and how fast you run your fans.
You might consider taking the stock heatsink on the card and cutting it up enough to get your water block on their but still use the remaining portion for ram sinks. Hopefully you can get the GPU block on and still retain enough mounting points on the stock HS to mount it effectively on the RAM.
Anyway good luck with the ramsinks.

Originally Posted by babybunny

I'm watercooling my 6800GT, which means I have to mount RAMsinks onto the 6800GT. I have a [L=MSI NX6800GT]http://www.msicomputer.com/product/p_spec.asp?model=NX6800GT-TD256&class=vga[/L]. It looks like it has the reference HSF.

Here's what happened:

1. Took off retail HSF, cleaned off remaining thermal compound with acetone.
NOTE: The thermal compound touching the RAM was a thick, pink, squishy material. It felt waxy to the touch. Definitely not sticky at all.

2. Put RAMsink on RAM. This is where it gets weird: The sinks would not adhere at all. They would actually SLIDE around on the RAM surface when moved lightly with a finger. Took off RAMsink, felt the bottom, and the thermal adhesive was definitely very very sticky.

3. Tried putting sink on a second time, this time applying pressure. Still the same thing.

4. Figured that the RAM surface was either oily or the adhesive is not strong enough.

5. Cleaned RAM surface with a bit of palmolive detergent (emulsifier). Replaced adhesive with a stickier kind.

6. Mounted sinks again. This time it is a little bit stronger, but can still be knocked off quite easily.

WTF is going on? Does anyone else have this trouble? Am I going to have to resort to a nonpermanent mixture of AS and thermal epoxy? What could be covering the RAM surface?

[babybunny]

Oh wow, thanks so much for that reply! I usually just take off the stock HSF and never give it a second glance when I watercool. In my case there is also a seperate HS for the memory that can be mounted on its own, so I guess I'll just use the stock memory HS then . Unfortunately I can't have my tubing pointing towards the front of the case because the bending required to reach the chipset cooler that's right next to the video card (on NForce3 boards) would be horrific and undoable.

Once again, thanks a lot. Oh yeah, I've never heard of this Goo Gone stuff. Does it take off that oily adhesive?

[ferdb]

Goo Gone is handy stuff. takes off all kinds of sticky icky stuff like tape and label adhesives, tars and oily/greasy materials. I think it even works on bubblegum. You can probably find it at supermarkets and walmart etc. It's basically one of those citrus based cleaners.

[ferdb]

By the way I'm using an Nforce3 board also (msi k8n neo plat). I didn't try to connect the hose from the GPU block directly to the chipset in a tight bend but looped it upwards and then down to the chipset block so I wouldn't have any tight radiuses. Also gives me plenty of slack tubing so I can remove the Vid Card without disconnecting the hoses too.