RAM Speed limit for XPS 15 9560 (Kaby lake)

Hello,

I just purchased a XPS 15 9650 model with in-built 16GB RAM. I need to max out to 32GB RAM
but, I've already came across different speeds like DDR4-2400, DDR4-2666 in a few manufacturers.

Could someone please help by advising the maximum RAM speed to go for XPS 15 9650
(where the entire speed is actually used by XPS 15) ?

I assume XPS 15 9650 has a certain limitation from which the excess speed becomes unused.
So, probably getting an extreme high speed is not worthwhile.

Kindly advise and Thank you,

 

According to Intel, the 7700HQ supports DDR4-2400, LPDDR3-2133 and DDR3L-1600. I just checked the memory speed on my 9560 and it is DDR4-2400. Then again, Dell does offer the Precision 7520 with a 7700HQ and a DDR4-2667 option so it might be compatible.

When you say you found DDR4-2666, do you mean that you've seen an XPS 15 with that RAM or that you found RAM of that type in a store?

 

I had seen those RAM types in stores (online) not on actual XPS 15 machine. For example on Crucial, they offer these:
Ballistix Sport LT 32GB Kit (2 x 16GB) DDR4-2400 SODIMM
Ballistix Sport LT 32GB Kit (2 x 16GB) DDR4-2666 SODIMM

Both of these are listed under the compatible sections for XPS 15 9650, but does this extra speed (2666) make an affect,
or would the hardware only pick speeds up to 2400 and the rest goes unused - this is what I'm trying to understand.

Although officially Dell says it takes DD4 - 2400MHz, some RAM models claim to offer compatibly for higher RAM speeds, which isn't officially a Dell's acknowledgement.

I do Analytics work with big datasets and I would want the best RAM speeds possible, just need to make sure XPS 15 actually uses it and not wasted.

 

You can buy 2667 or 2666 as some kits come as (both the same), they may drop back to 2400 speeds but this can also be beneficial over a stock 2400 kit as the 2400 latency will usually be lower.
Considering the 7520 isn't built on the same chassis as the 9560 you may just get 2400 speeds.

 

At Userbenchmark there are a few RAM high scores by G.SKILL 2666, it appears they run at 2666. Every 2666 may not.

 

When I was shopping for RAM, HyperX 2400 had the lowest CAS latency.

Low CAS latency might make your laptop a slight bit faster but good luck noticing any difference. Plus, there are so many bottlenecks in a small laptop and RAM is so expensive these days, I would be wary of paying extra money for low CAS latency RAM.

Fast, large nvme options may be a better place to invest in performance depending on your usage...

Edit - as a general matter as speed increases, unfortunately, so does CAS latency. So the "improvement" from 2400 to 2667 may be vanishingly small.

 

The truth is out there, so Buy, buy, buy, that is the only way to find out the truth. Newegg also have DDR4 3000MHz Sodimm!!!, so go ahead and report back, please!

 

Kaby Lake should easily eat 2800MHz of RAM.

FYI:
Skylake - max RAM frequency is 2666 MHz
Kaby Lake - max RAM frequency is 2800 MHz


I have upgraded my 9550 model with Corsair Vengeance 2666MHz RAM and it's works like a charm. Showing 2667MHz speed in BIOS and OS.

 

Good to know.

Sent from my SM-G920F using Tapatalk

 

How are you getting

Edit - As noted below there are some 6700HQ 9550 and Precision units running above 2133MHz. I don't think the i5 can...

 

Than you must have missed this thread. ;-)

http://forum.notebookreview.com/thr...9550-on-the-cheap.791494/page-2#post-10260395

 

Still waiting to see a 9550 running 2666?

 

100% sure. I have checked it several time and it always showing 1333*2=2666MHz.
I believe that key thing why it's happening lay in XMP memory profiles.

 

My error - apologies!

 

Keep up this great topic! Good to know 2666MHz working. But out there exist even 2800MHz and 3000MHz Sodimm modules. So go ahead guys and report back.

 

Why don't you?

 

If you check my signature you can see I do lot for the community, last time just purchased a little Kaby Lake laptop, just to see if will work with Windows 7 properly or not. It is not the only case when I was the guinea pig. To test DDR4 speeds I should buy laptop again and many RAM modules. Isn't just the buying the problem, but I also need to import them to Europe. Obviously sooner or later I'll do, but would be better just to get the right DDR4 modules.

 

anyone tried this yet ?

 

I checked UserBenchmark what can it say about Corsair SODIMM DDR4 3000MHz C16 2x8GB modules and noticed it is working at 2666MHz with I7-6700HQ. However no one tested yet with Kaby Lake.
If officially Sky Lake rated for 2133MHz and Kaby Lake for 2400Mhz speed, than there is good chance it will run at 2800MHz, maybe 3000...

 

There is Ram speed limit for Dell's newest Alienware line as well. Max supported is 2667MHz
Why should it be different with the other models from Dell? Maybe ask https://mobile.twitter.com/azorfrank Who is the Vice President for AW and the XPS line.

 

If you guys are using any modules at 2400MHz or more on your XPS 15 9550/9560, could you please report me that everything is looking fine on memtest86 (while running at least for 10 hours).

I just got in touch with Kingston tech support, and they told me that some errors usually appears on Dell laptops.
I'm trying to point out if this is related to either a bug in memtest86, a BIOS issue or just bad memory modules.

Especially for:

• Test 8 [Random number sequence]
• Test 9 [Modulo 20, Random pattern]

 

Never heard that before!

Sent from my SM-G920F using Tapatalk

 

Could also use TestMem5 several rounds. Can find ram problems who doesn't appear with Memtest.

 

Thanks for the link, I will test it right away.

PS: Is there any link to the official program?

Ok here it is: http://testmem.tz.ru/testmem5.htm (russian devs)

 

I'm on the go. You find it with Google. But the software link is safe.

 

I meant he was talking about the DDR4 modules who are not part of the JEDEC standard. (so anything above 2400MHz)

 

From my years of doing this any memtest error simply means the module isn't doing it's job at said speed. I had this complete idiot of an ebay seller flogging the 32gb kit of crucial 2400 for this but despite him selling them as tested he made a footnote that he tested on a 2133 board, needless to say I started getting random BSOD's that made no sense until I did a memtest and found a bad module, he started moaning he had tested them and the stick still tested ok (he had exchanged it without issue as I had told him what I did for a living and what I had done to test it along with the luxury of having 2 laptops to test with to rule out my hardware. I had to point out he was testing on hardware that wasn't capable of running it at it's default speed.

 

You find it, Ok. We put in + update useful software in NBR "unofficial" Software Updates