Is this m.2 Samsung 950 Pro thermal throttling in action?

[wpcoe]

When my 512GB 950 Pro was new, I ran CrystalDiskMark tests first with the Microsoft driver and then the Samsung (NVMe v.1) driver:

Today, after installing v.2 of the Samsung NVMe driver I decided to re-test using CDM:

While running the CDM tests a second time, I wondered about possible thermal throttling and HWMonitor reported the SSD temp as 77*C. This was in an un-air conditioned room with an estimated ambient temp of around 30* or 31*C. (I don’t know what the starting SSD temp was since I didn’t think about temps until the second CDM tests were running.)

Then, I turned on the air con, let it run for 45 minutes, and took the computer case cover off. With an estimated ambient temp of around 25* or 26*C I re-ran the CDM test starting with a SSD temp of 60*C. I ran each test separately with a pause between them to let the SSD temp to return to 60*C because it ramped up to 74*C during Seq Q32T1 read test (even with ambient temp cooler):

I didn’t think that the throttling would be such a factor in my home PC installation even here in the tropics, but I guess it is? Or, is there some other factor in play?

The Seq write speed now is even better than back in August when the SSD was new. Do you suppose that was due to thermal throttling at the time?

FYI, I ran the CDM tests today twice without air con and twice with air con. Results within each pair were very similar. My motherboard has the m.2 slot on the underside so airflow is not good (and why I removed the case cover for the second pair of tests.)

PS: While composing this post, the SSD temp dropped to 58*C.

 

[Valantar]

Where on your motherboard is your SSD mounted? Between the PCIe slots, beneath your GPU? That's a common placement, and less than ideal thermally. After all, even an idle GPU gives off some heat, and hinders air circulation above the SSD. Try getting some sort of thin heatsinks for it if it bothers you. Given that you haven't noticed any slowdowns, I wouldn't worry about it.

 

[FFFF]

Yep, looks like a classic case of M.2 NVMe drive throttling. Normal temperatures for your SSD are 1-70 ℃ per Samsung's official specs.

 

[Hail The Brain Slug]

Yep, looks like a classic case of M.2 NVMe drive throttling. Normal temperatures for your SSD are 1-70 ℃ per Samsung's official specs.

Yeah, I believe the 950 Pro begins throttling once it reaches 75C, and in some circumstances it can happen really fast.

Here's a 950 pro throttling test in a PCI-e add in card (with no heatsink)

Review link

As you can see, it was already throttling before the first CrystalDiskMark pass completed.

I just received my 960 Pro 1TB and noticed it throttling during my first CrystalDiskMark run, as well. I'm looking into where to find one of the kryoM.2 coolers in the linked review, but they are hard to come by in the US. (Doesn't help manufacturer direct requires a minimum $75 order and the thing is only $31.40)

 

[wpcoe]

It did seem that the throttling started at around 75*C.

As to the position of the SSD, I honestly can't remember which part of the mobo it's mounted to. I don't have a discrete graphics card, so at least that wouldn't be contributing to the heat-related throttling.

I've been watching the SSD temp, and it seems at idle, or low usage such as now while reading forums, it stays right at 60*C.

Somewhere I read about using some sort of adhesive thermal tape on top of the memory chips to help dissipate heat, and even better to keep layering the tape until it makes contact with the metal case. When I visit the USA in the spring I might try to find some. Trying to describe that in Thai, and to actually find it, is not worth the effort.

 

[Elixer]

The newer motherboards that have the dedicated heatsink for these units are really needed.
Lots of people have been yelling about the thermal throttling this and other units do quite often.

 

[Hail The Brain Slug]

The newer motherboards that have the dedicated heatsink for these units are really needed.
Lots of people have been yelling about the thermal throttling this and other units do quite often.

In the review I linked, they tested a 950 Pro with a cheaper add in card heatsink that is much bigger than any motherboard with a dedicated M.2 heatsink that I've seen. It improved the throttling but it didn't fully eliminate the issue.

With the size I have seen of the M.2 motherboard heatsinks so far, I think it would only help a little.

The 950 Pro is pretty mild as far as hot M.2 drives, too. I have a Toshiba RD400 on a system I've been working on for a while. The drive was thermal throttling immediately in CrystalDiskMark, so I attached a small aluminum heatsink directly over the controller.

It mostly keeps it from throttling in a single CrystalDiskMark bench, but the heatsink is so hot even while sitting at idle that it will burn you.

 

[wpcoe]

Well, this was unexpected: I finally got around to removing a very noisy AIO cooler that was installed in August. It was dead silent for about 60 days then started an annoying, intermittent grinding sound.

Yesterday the noise got to me enough that I pulled out the AIO and installed the standard Intel cooler that came with the CPU. That required removing the motherboard to access the backplate for the pump.

Reassembled everything and ran HWMonitor, and the Samsung 950 Pro is running about 10*C cooler! Right now, in un-airconditioned early afternoon heat, the SSD is steady at 50*C, whereas previously at idle it was 60*C.

Last night I was using air con (outdoor noise) and it was idling at 39*C -- I had *never* seen it that low before.

Running CrystalDiskMark will still provoke it into the lower 70's, though.

I wonder what caused the drop in temps, but don't want to jinx it.

 

[wpcoe]

The drive was thermal throttling immediately in CrystalDiskMark, so I attached a small aluminum heatsink directly over the controller.

Just noticed this comment above. Is it the controller chip whose heat causes the throttling? For some reason I "assumed" it was the NAND chips.

 

[Hail The Brain Slug]

Just noticed this comment above. Is it the controller chip whose heat causes the throttling? For some reason I "assumed" it was the NAND chips.

It's definitely the controller. While the nand can get hot, it's the temperature of the controller that determines thermal throttling, and its generally much hotter than the nand.

Thermal image of the 950 Pro under load.

The hot spot is the controller, the 82.5C spot is the dram, and the two NAND chips are visible (one is 76.7C and the other appears to be cooler than that.)

All the good coolers provide whole drive coverage and would keep all components cool, but if you're looking for a cheap and easy way to cool it down, my method with a tiny heatsink on the controller is what I came up with.

 

[wpcoe]

@XabanakFanatik, thanks for the explanation. The controller in that pic is *scorching* hot!

The 950 Pro is on the underside of my motherboard, so not a lot of room for a heatsink, but as mentioned, I've read about using layers of thermal tape (?) to build up a heat conductive layer to make contact with the bottom of the (metal) case.

I'm going to continue to monitor the SSD temp for a while. If the recent 10*C drop in temps continues, I may not need to be bothered at all. I don't think I do much that would tax the 950 Pro into high heat other than running CrystalDiskMark, but was not all that comfortable with a 60*C idle temp before.