Not that manufacturers always did good thermal choices.. I've a Radeon DDR original with the heatsink detached with the usual late 90's thermal fixed paste that not even covered 25% of the GPU (not even in the center) and now I don't know how to clean the GPU from it cause it's difficult to remove.

Use a citrus-based cleaner like Goo Gone and follow up with some 70% rubbing alcohol. This is the best way to clean off thermal paste and to remove any of the trace residue that gets left behind with a dry wipe or just alcohol alone.

Try cleaning a surface with just a try cloth or alcohol and then follow up with a citrus cleaner to see for yourself.

Unfortunately, this is of not help with epoxy which has to be carefully chiseled away.

Kahenraz wrote on 2021-09-07, 09:50:

Use a citrus-based cleaner like Goo Gone and follow up with some 70% rubbing alcohol. This is the best way to clean off thermal paste and to remove any of the trace residue that gets left behind with a dry wipe or just alcohol alone.

Try cleaning a surface with just a try cloth or alcohol and then follow up with a citrus cleaner to see for yourself.

Unfortunately, this is of not help with epoxy which has to be carefully chiseled away.

Belt sander......

In the first picture there might have been reason to use epoxy, if the components had not exactly the same height.
This might well have been a correction after production.

The "empty" heatsinks are purely for optics, I guess. Missing parts don't make such a lovely impression...

Its hard to tell from the photo but the components beneath the heatsink are identical and therefore all the same height.

The adhesive used was also a foam rather than a thin piece of double-sided 3M tape. So there is already some room for slight variance in height.

Kahenraz wrote on 2021-09-07, 09:50:

Use a citrus-based cleaner like Goo Gone and follow up with some 70% rubbing alcohol. This is the best way to clean off thermal paste and to remove any of the trace residue that gets left behind with a dry wipe or just alcohol alone.

Try cleaning a surface with just a try cloth or alcohol and then follow up with a citrus cleaner to see for yourself.

Unfortunately, this is of not help with epoxy which has to be carefully chiseled away.

Thanks, I'll try. Unfortunately the paste is solid as plastic on both the thin Radeon heatsink and the GPU. It's the only Radeon R100 DDR I own so I want to restore it cause it's a card I really want to collect.

Citric acid is a very mild and safe organic acid that will dissolve the compounds found in most thermal pastes. Applying alcohol afterwards is used to to neutralize and clean away any the residue that is left behind. I use cotton swabs for this and occasionally a nylon sludger if mechanical force needs to be applied to scrape away at any hardened paste.

If you have made a mess that is too difficult to clean with a cotton swab and are satisfied with the cleaning process, you can safely wash both the heatsink and the PCB in the sink with mild dish soap and an anti-static or fine hair brush. If you're careful as you work, this is rarely needed.

For cleaning PCBs in the sink with disk soap, follow up with compressed air to clear away any water trapped beneath any of the chips. While water will evaporate safely, the importance of this measure is to ensure that there is no soap is trapped beneath the chips. You'll know when there is no more soap by the absence of bubbles when blowing compressed air under it; if there are still soap bubbles then keep rinsing the chip and spraying compressed air until it's clear. I've used dish soap and water in this way to clean entire motherboards with great success. Just don't apply force while scrubbing as it's possible for surface mount components to break away; ask me how I know.

If that's an 8800GT, then those heatsinks are probably part of the Thermalright HR-01 GT aftermarket cooling solution. I know because I have one I bought shortly after getting the card, the heatsinks look exactly like that. So they were probably installed by the end user, not the manufacturer.

From what I remember the cooler itself was nice and kept the card at very low temps, but the thermal tape that came with the heatsinks was garbage and some of them fell off, so most people back then replaced it with something else (better tape or epoxy). Seems like the original owner of your card didn't care about removing the old tape before applying the epoxy.

Most of the heatsinks were for the RAM chips, however a couple of them were supposed to be placed on the VRMs, those are probably the ones that you found installed over empty spots, the owner probably didn't know where to put them. Incidentally, those were the ones who usually fell off due to the tape making poor contact with the VRMs.

Foam tape... that's a bit weird, as such better insulates than conducts.

Epoxy gets soft when sufficiently heated. Maybe it is easier to remove with a heated screwdriver (keeping the chip itself sufficiently cool).

Depending on how hot these get, the thermal conductivity may be enough to override the insulation properties of the foam. If a component gets too hot then the insulation properties will override the cooling provided by the heatsink.

This is why I can use thermal tape on a Socket 7 whose clip has broken off and the processor will still be adequately cooled. But if I were to try the same thing on a newer processor that runs at 65W, 95W, 135W... the processor will overheat in seconds. I've tried it. 20C in the BIOS with thermal paste and 95C with thermal tape with Celeron D.