RX 480 VRMs and aftermarket cooling woes

[DisarmedDespot]

I have a reference RX 480 and have never really been happy with the temps. I bought an Arctic Accelero Mono Plus cooler, slapped it on my RX 480 and the GPU temp dropped like a rock.

Problem is, the VRM temps skyrocketed. For anyone that doesn't know, the RX 480's VRMs are actually pretty beefy, but there's a bunch of smaller chips behind them that need cooled. After adding the new cooler, they hit 80-90 degrees and the GPU only clocks to 700-900 Mhz. If I turn the power limit to +50%, it reaches the full 1266 Mhz, but there's a buzzing I don't remember before and the VRM temperatures fly up to 115 degrees, where the card instantly downclocks.

Either the heatsinks included with the kit weren't enough, the included thermal adhesive wasn't good enough, or I'm an idiot and applied them wrong. I slapped as many heat sinks onto the card as I could with thermal tape, but I still needed the fan cranked to 100% to maintain full speed. I managed to remove the heatsinks without breaking anything, cleaned them with 91% isopropyl alcohol and put the stock cooler back on. The VRM temps were still terrible, so I replaced the thermal pad with Fujipoly Extreme ones (1.5mm). Same thing. I've opened the card up again, and all the chips are touching it, including what I think is the temperature sensor.

I don't think it's damaged, as I get the performance I expect before it overheats, and my UPS reports the same power draw as before. Is there something I'm missing? Any ideas what I might be doing wrong? Thermal pads don't need a certain amount of time to set, do they?

 

[IntelUser2000]

Are you sure you pasted them on the right spot? Like the following.

https://imgur.com/gallery/g76dM

The area where there are 14 black chips labeled MDU1514 is where you want to cover them. When I made my custom heatsinks, I made sure to cover all 14 of them. Heck, just to be sure I covered the big square inductors too! Then the main chip I used a zip tie to attach a Arctic Cooling Freezer 7 Pro. Ran like a champ. VRAM chips using eBay aluminum heatsinks.

I want a video card/laptop where every chip on the board is connected to a heatsink.

 

[DisarmedDespot]

Yep, put them right on those chips. I guess I didn't cover them well enough or the adhesive didn't take well enough. If all else fails, I might try to find some beefier heatsinks that'll fit and try slapping them on. For now, though, the stock heatsink isn't enough either.

 

[DisarmedDespot]

At this point I'm almost ready to junk the card. I've replaced the thermal pads again, this time with Thermal Grizzy Minus 8 pads. Tried both 1mm and 1.5mm, both of them hit 115 degrees and the card instantly downclocks.

What the hell am I doing wrong?

 

[killster1]

have you tried to point a 120mm fan directly to the side of the card? sounds like airflow issue and heatsink blocking proper flow of air over them. sometimes heatsinks make the temps higher for things. just my thoughts.

 

[IntelUser2000]

Could you take a picture and link it here? I'd like to take a closer look at what you did.

 

[DisarmedDespot]

have you tried to point a 120mm fan directly to the side of the card? sounds like airflow issue and heatsink blocking proper flow of air over them. sometimes heatsinks make the temps higher for things. just my thoughts.

Yup, tried that with both the Accelero Mono Plus and the stock cooler. I *could* keep the card from throttling with the Mono, but it required one 80mm fan as an exhaust and another pointed directly over the VRMs, all at full blast. With the stock cooler (for this test, shroud off), not even a 120mm fan for the GPU core heatsink with another 80mm fan for the VRM heatsink was enough. Air flow didn't seem to fix it.

Could you take a picture and link it here? I'd like to take a closer look at what you did.

Sure. Like I said, I managed to get the Mono kit's heatsinks off and put the stock cooler back on, but here's how the heatsinks looked when they were installed. I didn't want to use the square RAM heatsinks in the kit as they didn't cover the bigger black chips entirely (were just a little too narrow). I later stuck as many heatsinks as I could into the gaps with thermal tape, and it didn't fix the problem.

Here's what the stock cooler's VRM heatsink looks like, for anyone who doesn't know.

Here's what the Thermal Grizzy 1.5mm pad looks like after being removed. It looks like it's making good contact?

At this point I'm stumped. I've tried two different brands of thermal pads with the stock cooler and neither worked. The card isn't drawing more power than before, so either I'm terrible at applying thermal pads or I've broken the law of thermodynamics.

 

[IntelUser2000]

@DisarmedDespot

You did nothing wrong. The placement is correct for both the reference cooler and the Arctic Cooling one.
I fiddled with custom cooling for a long time. I think its not a good idea to do so, and if you do it, you'd want to do it with a new card, and never touch it after that.

That same reference card I was talking to you about, later on it was running 5-10 degrees higher, and when I put the reference cooler back on, it ran at much higher temps. Even though I didn't have problems with the VRM, something went wrong with your card, just as it was with mine. It could be a problem that's unique to the AMD reference RX cards.

I didn't want to use the square RAM heatsinks in the kit as they didn't cover the bigger black chips entirely (were just a little too narrow).

RAM sinks are quite important. They can run quite hot. Even applying half of the chip with the heatsink would help. That's what I did with my MSI RX 470 on the chips that couldn't fit the full heatsink. Bought a 2mm high heatsink from eBay so it can fit below the cooler. With the Accelero Mono, I've read that 1-2 sinks can't fit fully.

 

[Soulkeeper]

Those cheesy aluminum heatsinks that come with Arctic Accelero and other brands are mostly just for looks.
In some cases they might even make cooling worse by insulating/covering the mem and reducing airflow
The enzotech copper ones are the best but they can be pricey.

In my experience the case intake fan has the biggest effect on gpu temps. Even more than the gpu fan speed itself.
crank that thing up, and maybe that'll help

 

[William Gaatjes]

Airflow is very important , as is the size and the mass of the heatsink. Thermal resistance is everything.
Heatsinks with fins may never be placed perpendicular to the airflow. The airflow must flow in between the fins for maximum transfer of heat.

 

[Fc_Pennerschnaps]

My english isnt that good.. just buyed the custom cooler a half year ago and have the same problems now with 90 degrees on average can someone tell wich size is good for the heatsink and should i take copper or aluminum?