New guy posting in a somewhat old thread (but still relevant since the x570 is still the latest gen), thought I'd share what I found after some experiments... I have been playing around with my Phantom x570 Gaming X from Asrock (these are specific to this MB but probably applicable to all x570 MBs, at least Asrock's lineup that share the same heat sink and fan design). In none of the reviews did I see mention of the x570 chipset temperature, honestly I may have reconsidered had I know. I do have a few SATA SSDs, 1HDD, and 1 Gen4 4X M.2 SSD, but it's not like every slot is full... After trying a couple of different things over the course of about a week, I have finally got the idle temp to around 58C at idle with the fan around 2700RPM, and around 60C with the fan off after about an hour (down from around ~65C with the fan at like ~4k RPM).
I've done a few things to get it down some more invasive than others, the easiest was to just shut the LEDs off, (why you put LEDs on a "heat sink"...?), I think this dropped the idle about a degree C (it jumps around so it's a little hard to really tell, and I'm using Asrock's "Phantom Game Tuning" SW which doesn't give out graphs...). That's pretty straightforward, the LEDs are probably not using that much power, but depending on how many they have in there it could be upwards of 0.5W... not a ton of power, but going for "as low as possible" so anything was useful. It's hard to tell exactly where the LEDs are placed inside the clear plastic layer, but it's still attached and pretty much directly over the SB heat sink. If you do the more invasive steps below this is not optional...
The other simple one was to move the graphics card to the middle slot. The SB fan intake is really obscured by long cards and you end up sucking heat right of the graphics card... a great way to cool a chipset. MBs without the 2 or 3 video card slots obviously don't have this luxury. I think this was also another couple C drop, I did see a somewhat similar drop when I turned on the video card fans at idle, but under load, it seemed to start to get warm fast still.
The rest were more invasive. I actually ended up ripping the LED cover off the top of the protective/cosmetic cover plate, it's a thick layer of plastic and basically just makes a little oven out of that crappy heat sink. It looks like all of the similar Asrock x570s have this same cover, even if there's no LEDs. I actually think this made the biggest difference, maybe 3-4C. I put my finger on that cover under load (after I had shut the LEDs off, I probably should have checked before too), and it was barely warm after hours of being on. The metal on the plate was warm, so I knew that there's a lot of insulation going on there... I think the marketing folks won over the engineers on these boards... "Oh, it will raise the SB temp by 5C? But it will look cool, right? Let's do it!". After that was off, I took the metal grill plate off of the top of the removed LED piece and mounted it back on the cover plate, this was probably way overkill but I peeled some of the adhesive off of it where it sits over the chipset, and I bent the grill such that it would direct airflow down into the SB fan intake as air moves from the front of the case to back (I think this is also an issue, the SB fan is sucking in high-pressure air and moving it to... high-pressure areas...? trying to create a higher pressure on the intake side by directing moving air there) and then mounted it back on with some thermal paste in the area where I had removed adhesive. I also stuffed up the exhaust side with some thermal pad, it is blowing air towards the RAM slots, there's nothing to cool on that side of the heat sink... you just lose airflow across the hot parts that need it....
On top of this, I took off the entire heat sink, and then applied moar thermal tape to the chipset itself. At first, I tried a thick layer of thermal paste but I wasn't happy with it, I opened it up, cleaned it and applied the tape over the entire surface, including the substrate of the chip (the PCBA the chip itself is mounted on). It's a thick gap so I had to put two layers, unfortunately, but there is now much more surface area for the heat transfer. I also rolled up a piece of the thermal tape and sat it on an open area of the board directly next to the chipset to try to get heat out of the PCB. I also added a bit of thermal tape to a DCDC regulator or MOSFET and a DCDC regulator inductor that sit under the heat sink. I also seem to notice my MB temp is lower, but I wasn't really tracking it so I'm not sure how much, I'm not sure where that temp is taken on the board but it seems like one of these things also brought the MB temp down a couple of C (but it's also possible that clogging up the heat sink on the RAM side prevented the SB fan from spewing its hot air all over the MB, IDK.) I then doused the entire board with thermal paste. (ok, you got me, I didn't do that last one...).
Finally, I added another case fan. I have an Antek P100 case, with two 140mm fans in the front (air pressure blade on the bottom, airflow blade on the top fan, the top one basically just pushes air through the AIO cooler radiator, the bottom one is pushing air out the video card and hopefully through the SB fan...), a corsair H115i Pro AIO cooler mounted on the top, and one "hybrid" fan blade on the back. I've sealed all gaps except for the fans and the video card exhaust and have a front to back/top airflow setup. The P100 does not have a mounting position for a fan in the middle of the case on the hard drive slide rack (just front, back, top and PSU), so I zip-tied a 140mm air pressure case fan centered on the video card, figuring it will force some air out the video card exhaust (and over the heat sinks), and also blow air upwards over the SB chipset fan and my "hood scoop" I made by bending the grill.
The only thing I would like to try (I did all the above while it was in the case... super hard to get that heatsink off... had to get the board about halfway out...) is to take off the backplate and then load that up with thermal tape so that the back of the MB under the SB has the backplate as a heat sink, and then potentially putting some thermal tape onto the backplate such that it contacts the case side. I would bet this could get another couple C out of the chipset. I have considered adding a small heat sink to the top of the existing heat sink (yo, I heard you like heat sinks so we put heat sinks on yo heat sinks, yo) but the top of the cover plate does not feel that warm, so I doubt it would help very much except for maybe under load. I am hoping the thermal paste I added to the metal grill will help that act like another heat pad, and with the bend in it, air flows over part of that even when the SB fan is off.
There was one more thing, and I'm not sure if I did this while installing the M.2 SDD or it came this way (and it was early in my journey, so I don't know that it made any difference initially anyways, I think it would have after later mods), but the SB fan wire was jammed between the cosmetic plate and the heat sink so that the cosmetic plate wasn't making contact with the heat sink, and judging by the thermal pad they are trying to get heat out through that plate. I don't know that I *didn't* do that while installing the M.2 SDD, and with the LED cover still on the cover plate I don't know that it would have or did make a difference anyway, but that's also something to check. I did add more thermal paste between the heat sink and the cover plate upon the final installation to try to get more heat to conduct up that way.
Hope this help someone, I do think this is a problem even if AMD doesn't want to admit it. It could have been solved by the MB manufacturers but for some reason, they decided not to do it (hint: cost and cosmetics). It is technically "in spec" but why not build something to last. I keep my setups for a long time and I would like the chipset to last, as well as the fan. The SB fan (despite what the MB vendors will tell you...) is loud when it's running at high speed. If you have a "quiet" setup (I can run with only the WP in the AIO on), you will hear the SB fan. My 140mm fans at 500rpm almost make no noise, that tiny SB fan running at <5K RPM is noticeable and seems to almost do nothing. At 56C with the fan at 6k RPM, it's still 16C higher than anything else in my case.
