Leave it be, removing the heatsink can cause damage to the chip or components around the chip.

It absolutely can, you're right, though I've done freeze spray heatsink removal enough times that I'd think I'd be ok. That said, first time for anything, so not a thing I'd do unless it would have a tangible benefit.

Just put a fan on it, the risk isn't worth the gains, but you know this already.

Well, if I knew, I wouldn't be asking, I'm genuinely curious about how well old thermal glue can perform.

Not optimally and not adversely? I don't think there's a better answer. A fan is the best option to simply reduce the temperature, a heatsink replacement is for something more substantial.

Ok, so I'll leave it be and stick a fan on.

I've never really got the point of replacing thermal compound, it is only placed there too fill out any possible air gap/unevenness between chip & cooler, esp. if uneven surfaces, but still applied thinly to keep the cooler close to the chip for better heat conductivity.

Touch the backside of the card where the chip is. If it gets very hot compared to the heatsink, it indicates poor thermal conductivity. Only then you should consider replacing the thermal compound.

Well, for most older chips, the silicon chip itself is usually closer to the bottom of the package than the top, unless designed in an upside-down fashion, so heat is closer to the bottom. A good PCB should have a thicker internal copper layer for power & ground to spread the heat below the chip too. But YMMV.

My point was that you can assume a certain correlation between the backside and the heatsink temperature, and this can help you to determine if heat is properly absorbed into the heatsink. Touching the heatsink alone might yield a "false positive" for cards that are low powered enough. For this type of card and heatsink, the front and back temperatures are usually quite close to each other by feel, so you could easily tell if something was wrong.

RockstarRunner wrote on 2024-01-16, 19:07:

Ok, so I'll leave it be and stick a fan on.

Probably the best option if you're just concerned with longevity.

Rockstar is talking about adhesive, not thermal transfer compound, which is a different beast together. These are good tips though, absolutely the backside can be an indication of heatsink efficiency, still a voodoo science though. Speaking of voodoo ...

Rockstar, may I have your opinion on a matter, since there is no definitive consensus on whether this modification is of hindrance or benefit. 3dfx chose tiny heatsinks and fans for the Voodoo 5500 & 4500, presumably to fit the card to the single slot form factor, and it is known that these cards get hot on backside behind the GPUs. There are little holes behind the GPU, presumably to allow heat to escape more freely from between the GPU and the PCB. Other video cards don't have little holes, so is that their purpose? Are these hole there to compensate for the anemic cooling properties of the heatsink and fan? Here's the million dollar question, do you think adding a MOSFET heatsink that covers the little holes would end up being of benefit or hindrance to cooling properties of these cards? This isn't meant to alienate you, it's a question I have that nobody really knows the answer to. There is one person I can think of who might know for sure, his name's Hank, he designed these cards, he could probably tell us what the holes were for and his opinion about covering them would be the word of truth. I can add some pictures if you don't know what I'm talking about.

The holes are just vias, used for ground and power. Additionally, they help move the heat from the VSA into the PCB.
Adding a heatsink there definetly helps.
There is no airflow through those vias, so you can cover them up.

Noice, exactly what I wanted, confirmation from subject matter experts. I'm just a software monkey. 😀

I actually did this to my V5, as I figured more heatsinks couldn't hurt 😅 Good that sdz has a definitive answer, I was only guessing they were vias, and just went ahead and did it.
I had a Hercules Radeon 9700 Pro back in the day that came with a small heatsink on the back of the card, behind the chip, straight out of the box.
The V5 was nice and easy to freeze off the heatsinks, and has perfectly placed mounting holes for decent replacement heatsinks, wish the same could be said for the Viper Z200, anyway, I've fitted a noctua 40mm fan, and things seem ok.

@RockstarRunner
What heatsinks have you used? I have a few V4 and V5 cards without heatsinks, and I haven't yet found a decent replacement (didn't look that hard though).

sdz wrote on 2024-01-19, 16:10:

@RockstarRunner
What heatsinks have you used? I have a few V4 and V5 cards without heatsinks, and I haven't yet found a decent replacement (didn't look that hard though).

I bought some genuine copper ones from China, wasn't too expensive either, however you do need to order 10 at a time. Also bought smaller ones for the Vram too.

As for attaching them I used some high quality thermal tape, which seems counter intuitive but the high quality tape works just fine for the temps the VSA100 gets too.

Wow, I didn't know it looked like that on the backside, but there they are. Power and ground you say... interesting.

RockstarRunner wrote on 2024-01-19, 06:19:

The V5 was nice and easy to freeze off the heatsinks, and has perfectly placed mounting holes for decent replacement heatsinks, wish the same could be said for the Viper Z200, anyway, I've fitted a noctua 40mm fan, and things seem ok.

Yea, and unlike the V5, it's a big heatsink and it does a decent job for the stock settings so, in my opinion, not worth the risk for just longevity concerns. If you want to try for 200MHz then by all means ... pop it off!

Trashbytes wrote on 2024-01-19, 16:14:

sdz wrote on 2024-01-19, 16:10:

@RockstarRunner
What heatsinks have you used? I have a few V4 and V5 cards without heatsinks, and I haven't yet found a decent replacement (didn't look that hard though).

I bought some genuine copper ones from China, wasn't too expensive either, however you do need to order 10 at a time. Also bought smaller ones for the Vram too.

As for attaching them I used some high quality thermal tape, which seems counter intuitive but the high quality tape works just fine for the temps the VSA100 gets too.

Here's what I'm using, more expensive than Aliexpress offerings but they're nice quality. I've got three of these now. The orange mounting clip fits after honing the standoff holes with a small file.

https://www.enzotech.com/cnb_r1.htm

Here's what I did: Re: Voodoo 5 preventative maintenance
Though I hadn't attached the little heatsinks to the backside of the vsa's when I took the photos.

@RockstarRunner
Thank you! It's exactly what I was looking after.