XPS Desktops

[kalarous]

So here's a fun one. I too (as many on this forum have), have been having random system freezing issues with my Dell XPS 8940 with Nvidia RTX 3060 Ti video card. After a lengthy phone call with Dell support, the support engineer in their infinite wisdom has decided that the system doesn't have a hardware problem and if I'd like any further help resolving this situation, I can fork out another $100 for "software" support. System is less than 1 year old and still under warranty. I spent close to $2500 for what was supposed to be Dells "top of the line" Desktop. So, I'm left with 2 choices - either live with a problematic dell desktop or shell out another $100 for their software support and HOPE that their software support personal can help me fix this issue. Needless to say, I will be seriously considering whether or not to purchase ANYTHING else from Dell, ever.

[ishmael]

Been awhile since I installed the extra memory, so opened up the box to see where its installed. The Hynix is in slot#2 (channel#2) and the Crucial is in slot#4 (channel#1), and task mgr shows the memory is running 2933MHz. However, CPU-Z shows these sticks in different slots for whatever reason. Here are my screenshots.

[ispalten]

Hmm, what you have is you are using 2 Banks/Channels. Each DIMM is in its own channel, but it will run Dual Channel that way. It is also Single Rank, and that is not what I'd expect (assuming the Crucial DIMM is 2Rx16)? Each Bank/Channel should be its own Rank I'd think? Maybe not, if you have one Single Rank channel then that is how the Memory Controller works?

You might have 'solved' the CPU-Z slot naming method. Bank 1 is slots 2 and 4, and Bank 2 is 1 and 3. So in my case I'm in Slots 2 and 4, which is Bank 1 and CPU-Z reports my DIMMs in Slots 1 and 2, e.i., the first Banks slots. You see Slot 1 and 4, the 1st slot in Bank 1, and the last possible slot, the 2nd in Bank 2 which is 4.

Any, I am freeze with mixed Rank DIMMs in the first Bank, Slots 2 and 4.

This not the solution, using the same or different banks for DIMMs still fails.

Some have tried on Dual Rank and those have had failures too.

Seems everything is a dead-end so far. Yes, some with the Nvidia cards can work fine, but the reason is clearly unknown.

[ispalten]

By the way, since you are using both channels, and each is not fully populated, you might not be getting the full performance from the RAM. Go back and look at my CPU-Z captures from ‎07-28-2022 09:50 AM.

My Unicore Frequency is 4x or so what you have and Row Refresh Cycle Time is almost 2x as fast.

Move the Crucial DIMM to slot 4 (physical, 4th from the CPU) and I'd expect those numbers to match mine.

Not clear though if you'd notice and improvement or not? I guess it is if all Single Rank on one channel has the Memory Controller perform better than running 2 individual channels, one Single Rank, the other Dual?

[ishmael]

Not sure this is clear, here is where my memory is located. Note: slot#1 is closest slot to cpu.

Channel# 1: Slot# 1: empty, Slot# 3: Crucial
Channel# 2: Slot# 2: Hynix, Slot# 4: empty

I would think moving the Crucial to slot# 4 would eliminate dual channel. Yes? Also, it appears that Uncore frequency can vary up and down, at least looks that way in mine after just checking it compared to what I posted above.

[ispalten]

OK, i'll assume the Frequencies can vary? Mine appear solid though? Might be the configuration you have. don't know?

First, from what I've read, most sites when the talk about 'channels' or 'Bands' they assume 2 DIMMs in each.

When they talk about Dual and  Single channel, they also assume fully populated.

I've seen not that fits your specific case, 2 channels, one Single Rank, the other Double Rank.

In most cases, I've seen sites that consider only 2 DIMMs in a channel and do some measurements. Dual Channel is 'better' but it also depends on the application at the time.

I guess you can do some performance measurements yourself, as-is not and with them both on the same channel.

With both on the same channel, the Memory Controller only has to deal with one channel, and that, to me, would mean less switching between channels. I assume that means less time lost not accessing RAM.

If you do find out that what you did is faster, post it here, I am interested in that.

I also suggest you move the Crucial to Slot 4 and use CPU-Z to see if those frequencies are higher? Lower readings could be due to the Memory Controller looking for the empty slots to see what they contain, and in my case they are all in one channel.

[ishmael]

My understanding, when utilizing dual channel, is that the system will access both channels simultaneously. https://beebom.com/single-channel-vs-dual-channel-memory/ In terms of performance, studies show only slight improvement. But if you have the right amount of the right memory sticks then there does not appear to be any good reason to not configure dual channel.

Can you show the cpu-z output for your configuration and which slots exactly are your memory sticks located in. Also, can you post the memory speed from task manager/performance /memory.
Btw, the command wmic devicelocator also does not show the actual slot either, similar to cpu-z. See, https://social.technet.microsoft.com/Forums/en-US/87d923a3-5f84-4ae9-a61b-32c65e76a6ae/actual-ram-sl...

[ispalten]

I already posted my CPU-Z captures @ 07-28-2022 08:50 AM in this thread. Look at those.

Yes, I am running @ 2933Mhz speed. You can see that too in CPU-Z, since it is DDR4 RAM, you multiply the CPU-Z speed by 2. Same value than that I see in Task Manager:

By the way, if you get AIDA64 (not free but there is a free trial) it does show the correct SLOTS that the DIMM's are in, naming them DIMM 1 through 4. Yes, WMIC shows it wrong too, I posted those in another tread here too.

It is probably due to how the programs read the DIMM location I guess? However, AIDA64 proves it is possible to get the slots right.

Still, this is off the subject here, RAM and how configured doesn't seem to be the trigger or cause of the lock-ups.

I am aware that performance difference are minimal at best. I am thinking if the memory controller has to work with 2 DIMM's on one channel it 'might' be faster than one DIMM each on each channel?  Assuming that is correct, however, it is possible one being Dual Rank could offset or do better in that configuration. In any event, one would probably never notice that, expect possible in some Performance testing programs?

If I want to be SURE, I'd replace the Single Rank DIMM and have both Dual Rank DIMMs on the first channel.

There are links on the web that sort of say that:

https://diamondlobby.com/tech-guides/how-to-enable-dual-channel-ram/ 

That one could be right, I'm not sure? Problem is is CPU-Z correct? That is are you really running Dual Channel AND Dual Rank on 1 channel? 

Another, https://www.techradar.com/how-to/how-to-install-ram  and it doesn't even consider Dual or Single Rank?

Want some more confusion, https://www.compuram.de/blog/en/single-dual-and-multi-channel-memory-modes/ and it confuses RANK with how many sides chips are on.

I am not sure there is a real difference no matter how you install them. I also don't trust CPU-Z's data for slots. I am also not sure about mixing Single and Dual Banks/Channels offers an plus over both Ranks on one bank running Single as the Memory Controller doesn't need to switch banks and saves some time that way? 

Doesn't matter I guess, both work, and has no bearing on this problem here.

[ishmael]

Okay, found your cpu-z screenshots.  Was having trouble earlier due to Dell's formatting problem (which am glad they got fixed) trying to find or see things.  It's interesting then that you have your RAM in slots 2 and 4, which according to my info should mean you are only using Channel# 2, color coded black.  But cpu-Z obviously says you are in two channel mode: 2 x 64-bit.   I think I just assumed I needed to have one stick in Channel# 1 (white coded) and one stick in Channel# 2 (black) to get dual channel running at 2933MHz, which is obviously not true.  I came to this conclusion from reading https://www.dell.com/community/XPS-Desktops/XPS-8940-SE-third-party-RAM-cannot-run-at-2933MHz/td-p/7...

Where the author states "don't have the same brand of memory in either channel," and so set mine up accordingly.

Regarding RAM rank, which indeed adds more confusion at least for me, I have not encountered that variable until now.  I do see that your micron stick's Rank says single whereas mine says dual, but have no idea if that means anything related to freezing or performance.

I agree that it does not appear one's memory configuration, as long as it works, on the xps 8940 has anything to do with this freezing/locking issue.  Sorry about that, since our configurations appear to be very close. 

[ispalten]

Maybe your 8940 slot colors are different from mine, but from the CPU they alternate black and white slots. That is Black is slots 1 and 3,  White is 2 and 4. White slot 2 from the CPU is where Dell installs the first DIMM when you have a single DIMM as I had. That is the White Clips first.

See https://www.cgdirector.com/ram-slots-use/ as well.

I don't think the Channel # is that important as is the spacing from the CPU for heat and air flow.

Here is the Motherboard picture:

DIMM 1 and 2 are in Channel 1/Bank 0, and have the White Clips as you can see. These 2 White slots it appears is what CPU-Z calls Slot1 and 2?

[ishmael]

You are correct and my notes are not.  From the CPU: Slots 1 & 3 are Black, Slots 2 & 4 are White.  Is the memory the only thing you added or replaced on your xps 8940?    Did your pc freeze before adding the memory?