G15 5511 2nd M.2 Drive Issues

I just want to add to all the posts regarding Gen4 drive issues. I, too, have a Crucial P5+ Gen4 drive. Works fine with the Gen3 slot, with performance capped at Gen3, but when it is in Gen4 slot, it either works sluggishly with eventual freezes and bluescreen, or not able to boot from it at all.

I have been emailing Dell's tech support since 12/9, and their latest reply to me is basically that there is not a problem as far as they are concerned, and that my system is working as designed.

I am also really disappointed as I bought the 5511 over other choices largely because of their claim on Gen4 capability, and so far that capability is non-existent. My email with them is not quite done yet. If I have anything helpful, I will be sure to update here. Just know that we are not alone...

Greetings,

I believe I can shed some light on the PCIe NVMe SSD problem: heat. That's why you cannot attain and/or sustain the high speed and it's why the results can be unreliable. I just received my G15 today and the first thing I did was remove the bottom cover to inspect it. I'm certain that there is not adequate cooling for sustained Gen 3, and certainly not Gen 4 speeds. Dell provides only a thin, flat copper thermal shield. This is entirely inadequate with the mediocre air flow around the two M.2 mounts. So it's no surprise that they handle benchmark tests poorly.

To make matters worse, the thermal shield does not make direct contact to the silicon on the SSD. Ideally, the chips should be bare (no stickers) and a high quality thermal pad (or better yet, thermal paste) used to make the mechanical connection. So, the first thing I would do with a third-party SSD is remove the stickers and clean the adhesive from the chips before connecting the thermal pad of the shield to them. Unfortunately the flat design of the thin thermal shield provided by Dell is too flexible (with just two screws to anchor it) and will probably not facilitate the best thermal contact with paste and we're forced to stay with thermal pads. And, if you're forced to buy a third-party thermal shield, who can say how good the provided thermal pad is?! It might be wise to buy good pads from a known manufacturer.

Most users don't realize how hot PCIe NVMe SSDs can get---especially at Gen 3 and Gen 4 speeds. You can quickly degrade them and ruin them with too much heat. That's one of the secrets of the best Pro PCIe NVMe models---they have an extra thick internal metal layer to conduct heat out of the chip. Sustained use at these speeds is not safely possible without exceptional cooling.

For computer design, it requires both a good heatsink on top of the chips (and there's no room for that in the G15 chassis) and excellent air flow (the G15 chassis cooling is directed primarily at the CPU, GPU and RAM). As far as I can tell there are no air vents for the M.2 mounts (the bottom cover vents appear to stop short of them).

Another thing that most users do not realize is this: Each PCIe NVMe SSD model should be individually supported by the computer BIOS. Why? Because the BIOS needs to know the thermal profile of each SSD so it can properly regulate it. Unless things have changed with Gen 3 and 4 to overcome this issue (I'm unaware if they have), it is the single greatest flaw of the PCIe NVMe implementation and it's one reason why you can get into trouble when you stray from factory-supported models.

It would be nice if Dell would provide a full list of all PCIe NVMe SSD models that each new version of their G15 BIOS supports. But this is rare because most manufacturers want you to buy their parts. It's hard to fault this when you consider that they often sell the computer at such a razor thin margin. The price competition in gaming gear is huge---especially at the lower end like the G15 line.

But without better M.2 cooling in the G15 chassis, BIOS support will never be enough to sustain Gen 3 and Gen 4 speeds. Sadly, these hot SSDs are best used in desktops. You'll have to decide if a Gen 2, 3 or 4 is best for you based on how much you expect your SSDs to see sustained use. I plan to upgrade to two 2 TB SSDs in a mirrored RAID-1 array (a requirement for my application). I doubt I'll go any higher than Gen 3---and I will try to devise a better heatsink than the factory one. ... But that will have to wait until I have time (probably next summer).

I hope my comments are helpful. It's been quite a few years since I posted in these forums and this discussion caught my eye when I was searching for M.2 mounting parts (which I found at Amazon) for my new G15.

Kind regards, Thot

even if the chassis is opend, with a aftermarket nvme cooler and additional fan, nvme temperatur @ 34°C the ssd wont work in PCIE4.0 Mode. 

there is a difference between failure and thermal throtling.

in first place i thought the same, because the WD SN850 hitting 75°C with the original dell nvme thermal shield.

for me the PCIE 3.0 Speed in second slot is okay, but iam dissapointed from dell.

---

@stanley1946 wrote:

Ithe email chain with tech support is now moving forward to a "system exchange" - they said the replacement will not have the same problem - I am not so sure at this point, so I will wait and see for when I get the replacement unit, and see if it is indeed fixed.

---

I'd be curious to see if what they send you is a different hardware revision of the motherboard. I know I've said it many times in this thread, but hopefully Dell can fix this with a BIOS release.

Hi Votava and stanley1946, et al,

Thanks for the reminder: there are separate issues being discussed here and I tried to hit them in my first post. But I guess I didn't differentiate them as well as I should. Apologies. You guys appear to understand this stuff, but I'll summarize it below for the sake of less-experienced readers...
 

Issue 1 - The SSD never works
This could be a hardware or firmware issue.

The best solution is preventative---check with Dell, the SSD manufacturer and/or other users before you purchase an SSD to make sure that it is a compatible SSD model for your model G15. Otherwise, here are the possibilities to explore:

• The SSD, itself, may be defective or incompatible. Test the SSD with a different model PC to determine if it works at all. If it does not, it is probably defective. If it does work with a different PC, the issue with your G15 may be compatibility. If it is not compatible, you should switch to an SSD model that is compatible or you could wait and hope that Dell will release a firmware update that makes it compatible. Personally, I wouldn't wait---there's no guarantee that Dell will ever release a firmware update that fixes your specific issue.
• The G15 hardware (motherboard) may be defective or incompatible. Test the SSD with another similar G15 having the same motherboard to determine if the first motherboard is defective. If the SSD works with the second G15, then the motherboard of the first G15 is probably defective. If you think the motherboard is the problem, contact Dell for support.
• The G15 BIOS firmware may not support the specific SSD model. If you think you have a firmware problem, the first thing to do is to make sure the settings for the old SSD are cleared. This is done by resetting the BIOS and EC settings (make sure to record all your BIOS settings beforehand so you can restore them afterward). Your G15 should notice the new SSD when you reboot after the reset and update the firmware settings. If this didn't help, contact Dell for support or switch to an SSD model that is supported by the firmware.

 
Issue 2 - The SSD works but never achieves the full rated speed
This could be a hardware, firmware or thermal issue.

Regarding hardware, Dell's G15 specs state that each of the two M.2 slots have four PCIe lanes and they support Gen 3 (approx 3500 MB/s reads) and Gen 4 (approx 7000 MB/s reads). (That's Gen 3x4 and Gen 4x4.) However, as some of the previous posts in this thread have described, it appears that only the first M.2 slot is Gen 4 and the second slot is limited to Gen 3.

• With hardware, the lowest generation always sets the speed limit. If you have a Gen 3 slot, you'll only get Gen 3 speed from a Gen 4 SSD. Similarly, if you have a Gen 3 SSD, it will only yield Gen 3 speed even when it is plugged into a Gen 4 slot.
• Along a similar line, if you plan to combine two SSDs into a RAID array (either striped RAID-0 or mirrored RAID-1), each individual SSD in the array will operate no faster than the slowest member. Since one of the M.2 slots seems to stop at Gen 3, there is no reason to ever use a Gen 4 SSD if you plan to use it in a RAID array in your G15. And it's wisest to use identical models inside a RAID array.
• If you install a Gen 4 SSD into your first M.2 slot (which is reported to be Gen 4 also) but you still cannot exceed Gen 3 speed, you may have a firmware issue. This can take two forms: (1) Your firmware may support your new SSD, but the system settings for your old SSD are still active. The solution is to reset your BIOS and EC settings so the BIOS will recognize the SSD change when you reboot and update its settings. However, before you do this, you should carefully document all of your current BIOS settings so you can restore the rest after the reset. (2) Your firmware may not support the new SSD model. Unfortunately, the only solution in this case is for Dell to provide a firmware update with the needed support. But there's no guarantee this will happen.
• In my opinion, the G15 does not have sufficient cooling for sustained use of a Gen 4 SSD. The best you can hope for is to achieve Gen 4 speed briefly for transient bursts. The G15 chassis is not designed for sustained high-speed use so the SSD cooling may need modification. At the very least, you could remove the bottom cover and add an external fan like Votava described. However, doing so can create both an electrical safety hazard and RFI (radio frequency interference) problems.

 
Issue 3 - The SSD works and achieves the rated speed at first, then slows
This almost always indicates a thermal (cooling) issue. You can try to augment your cooling as I describe below, but the best---and safest solution---may be to switch to a cooler SSD. If you are trying to use a Gen 4 SSD, switch to a Gen 3 or Gen 2 SSD.

All M.2 NVMe PCIe SSDs run significantly hotter than M.2 SATA SSDs and the SSD manufacturers know this. So they include thermal protection circuits in their NVMe PCIe models. It throttles the SSD to a slower speed when it gets too hot. Based on my experience, these protection circuits can be overwhelmed when the airflow is inadequate, causing permanent degradation of the SSD or adjacent circuitry. The problem is worse in the tight confines inside our G15 laptops because there is no direct venting at the SSD locations and the fans do not draw air by them. This means that the SSD and/or adjacent circuitry can continue to cook for a while even after thermal throttling has begun. If degradation occurs it may be permanent and you may never be able to get your SSD to run at full speed again---even if it is adequately cooled. And you'll probably have reduced its lifespan.

 
Issue 4 - The SSD works at first but it sometimes disappears
This could indicate a thermal or compatibility issue. Or it could indicate defective hardware.

• If the SSD disappears after it gets hot, that's probably a thermal issue and you need to find a way to cool it better or you may need to switch to a cooler SSD model (if you're using a Gen 4 SSD, switch to a Gen 3 or 2 model).
• However, if the SSD disappears when you are sure it is still cool (for example, it sometimes doesn't appear when you cold-boot your laptop (and your laptop is cool), then it may be a compatibility issue. Sometimes compatibility problems can be intermittent and relate to subtle timing problems over the PCIe interface.
• Unfortunately, intermittent disappearance could also indicate a defect and this can be difficult to troubleshoot. This is because either the SSD or the G15 motherboard could be defective. Or both. Troubleshooting is usually a process of elimination, starting by replacing the cheapest, easiest parts first (the SSD) and, if the problem persists, moving to replacing the more expensive, difficult parts next (the motherboard).

 
How to augment the SSD cooling in your G15
I have an idea how to safely augment the cooling of the SSDs in my G15 and I ordered the parts yesterday. But I probably won't try to implement it until the summer when I install new SSDs. My plan involves two parts:

First, I'm going to replace the thermal pad between the copper heatsink plate (Dell calls it a "thermal shield") and the SSD with a much higher-quality pad. As I understand it, Dell uses Laird pads with a thermal conductance of only 1.2 W/(mK). I plan to use GP-Ultimate pads from Gelid rated at 15 W/(mK). That's 12.5x more heat transfer.

Second, I'm going to attempt to increase the surface area and mass of the stock copper thermal shield by bonding a second 2 mm copper heatsink to it. I've made preliminary measurements of the clearance between my bottom cover and the factory thermal shield and I think there is room for the additional 2 mm heatsink---but I'm not sure. Unfortunately, I waited too long to order the heatsinks and my supplier ran out of stock, so I had to order them direct from China, which means they may not arrive for a month or more.

Together, these two mods should lower the temperature 5-10°C, but I'm hoping for 20° or more. My goal is to keep the SSDs under 100°C during peak load and under 50°C while idling. But one of the problems I anticipate is the upside-down nature of the G15's SSD mounting. Since they face down and mount to the bottom of the motherboard, the thermal shields are on the bottom. This will cause the heat from the thermal shield to rise upward, toward the SSD. It kind of partially defeats the purpose. Since heat rises, you generally want your heatsink on top when the airflow is low. Dell did not make this easy!

 
Kind regards, Thot

I found this video on youtube. The guy compare the stock thermal pad and two thermal pads with different thickness.

The results are very interesting. Because the memory and controller are not the same height, applying the right thickness of pads will lower the temps considerably. For the 970evo plus and 980 pro, he uses thermal pads thickness of 1mm and 0.5mm. The results shown that the controller with proper thermal pad thickness (1mm) will gain 10C cooler on heavy load.

Hi YtRaWr,

Great observation! Details like careful pad thickness matching can have a big effect on thermal conductance. I already anticipated this same issue and purchased Gelid GP-Ultimate pads in both 0.5 and 1.0 mm thicknesses. So I should be covered. By the way, I measured the stock pad provided by Dell and it is 0.5 mm thick.

Another thing to consider is whether or not to remove the sticker on the top of the SSD. The stickers on most M.2 PCIe NVMe SSDs are reported to be made of a metallic foil with good thermal conductivity so you don't need to remove the sticker when you press the pad against it. And many SSD manufacturers will void their warranty if you remove the sticker.

But for the best heatsink installation you should remove the stickers and clean off any residue of adhesive. Then cut an individual thermal pad to fit the top of each chip separately. By covering the top of each chip with its own pad of the correct thickness you accomplish two goals: (1) achieve the best contact between the heatsink and each chip, and (2) leave as much opening between the chips as possible to facilitate airflow.

In the case of the G15 chassis, it will only be the mild airflow created by convective heat transfer because the fans don't blow air to the M.2 SSDs and there are no vents over them. But the idea is to remove as many layers as possible between the chips and the heatsink while also maximizing the exposed surface area where the chips do not contact the pad.

Kind regards, Thot

like said before its no thermal issue on the samsung 980 pro or wd sn850. on 30-40 degrees the transfer speeds are low or system freezes on PCIE4.0. I think its a failure in the mainboard or bios. In PCIE 3.0

mode an without thermal shielding on 75 degrees the wd sn 850 works fine. measured with WD Dashboard. 

@Votava,

Sorry, I thought I made it clear earlier that I agreed with you. In your case the low performance does not appear to be a thermal issue. But the symptoms being reported in this thread by others may not be the same and some of the other cases may result from an obvious flaw in the design of the G15 5511 chassis---inadequate SSD cooling.

What I'm focused on is different from you. You want to get something to work that hasn't worked yet (achieve Gen 4 speed from a Samsung 980 Pro and/or WD SN850) in your laptop. My concern is for long-duration sustained write performance in my laptop. As long as you cannot get either SSD up to full speed, you have no idea how long their performance can be sustained in your laptop because you cannot test it.

Based on what I've seen so far, I doubt that either Gen 3 or 4 speeds can be sustained as long as I need in my G15 5511 with the SSD models offered by Dell. Yet I think I may have a solution. I found a line of M.2 PCIe NVMe SSDs that are the first to use a new kind of 128-layer NAND flash-memory chip and they claim their SSDs run much cooler than everyone else. Together with augmented cooling, I think I may be able to get what I need from my G15 5511.

The line in question is the SK hynix Gold P31 and they are only offered for Gen 3 currently. I'm not aware of anyone using them yet in a G15 5511 (anyone reading this who has used one in their G15, please let me know).

I've corresponded with Dell support about them and they believe they will work (Dell says there shouldn't be a firmware problem). But I need the model with the largest storage capacity (2 TB) and Dell support seems hung up on the idea that a 2 TB SSD needs to be Gen 4 to work in the G15 5511. I can't imagine why this would be true and I believe it's just a hangover from a typo in the Dell G15 5511 Setup Guide. All of the models in the SK hynix Gold P31 M.2 line are Gen 3 and their write speed of 3200 MB/s is way more than enough for my needs. I just need to avoid it being throttled down below 500 MB/s due to overheating.

Besides, Gen 4 would be a waste for my needs because I have to configure two of them in a mirrored RAID-1 array and, with the second M.2 slot in the G15 5511 supporting only Gen 3, the max speed of the RAID array would be Gen 3. But, even if the second M.2 slot could do Gen 4, I'd probably choose Gen 3 devices anyway because they run cooler.

Kind regards, Thot

Just to provide an update on my situation/system exchange. Dell eventually got to the point where they provide the specs of my current system and the specs of the exchange unit, and ask if that is acceptable. It's slightly nicer than my current one, so I replied acceptable, which should have started their process to prepare a shipment. The latest I heard was on 12/30, and they told me the ETA (once I gave them the confirmation) is 5-6 days. Well, to date, no package, no replies, no nothing. Dell support is simply ignoring me. I tried to ask for at least tracking and shipment details, and now they simply ignore my emails (when I first started contacting them for help, they replied all my emails within a day, even on Saturday, at most 2 days).

So, based on that, I am not even sure if they will follow through with trying a new unit. My first email was sent on 12/10, and so far there has simply been a lot of circling around. If I get any substantial development, I will post again.

Dell Support private messaged me here after my post above - it appears they are of a different team of support people than the ones I have been dealing with via emails. The person was quite nice about the situation I raised and after I cooperated with giving me the relevant case number and such, he said he will escalate the case and have updates in 24-48 hours. Will update again soon.

I can confirm the latest BIOS released just today did not resolve my issues with Gen4, so based on Thot's detailed scenarios, my issue is likely with the BIOS (still) or hardware defects. As I said above, a different team of Dell Support reached out to me privately and is working on the stalled system exchange. That is still my hope to fixing the issue for now. Will update again when I have news. Cheers.

same here PCIE4.0 dont work on Bios 1.9

Still no real progress since 12/21. I have essentially been told several times to be patient and wait for updates.

My guess is it's partly due to the current events with COVID and shipping delays, but it's still frustrating that it takes that long to a new replacement unit shipped out, when it needed only a few days for me to get my current G15 between my purchase and its arrival.

I bought the L502x (which, still runs by the way) back in 2011 and had a bunch of issues, too. SSD, power adapter, and something else, but they were able to fix things or have new parts/unit replaced for me in less than a week. My current experience so far is just very different.

Has anyone reliably fixed their Gen4 issues?