Dell XPS 15 9560 - Anyone with 56 WHR battery running both a M.2 SSD & 2.5" Hard Drive

Considering getting a Dell XPS 15 9560 and was wondering if anyone who has it with the 56 WHR battery is running both the M.2 SSD & 2.5" hard drive.

If you have both the M.2 SSD & 2.5" SATA hard drive will it only run up to SATA 150 speeds?

I read that M.2 SSD drive will likely consume the bandwidth that's available for the 2.5" SSD connector.

 

So I decided to update my intel graphics driver to the newer 4590 one and upon reboot my Bluetooth mouse stopped working....I have tried everything that I can think of but my computer will not find it or my other one. I have tried to do multiple system restores which all fail, I have uninstalled the intel driver and reinstalled the one from the dell site, I have updated the killer and Bluetooth drivers to the newest on the dell site and nothing is working. Anyone else have any ideas? Thanks

 

Do a search here on the 9550 threads as one person tested the 2.5" bay speeds using a SSD and said it was slow. Find his name and send him a message.

The 9560 might be different but I don't see why...

 

Aida 64 doesn't report shared PCIe ports so it should be sata6 speed.

Wrong thread?

 

@GoNz0 so the older XPS 15 9550 had the shared PCIe ports?

 

I Didn't think the old one was shared, 2 separate technology's, ones a sata interface, the other pcie. Maybe someone with 2 drives can check in aida64?

Sent from my SM-G920F using Tapatalk

 

You will be fine. Both drives will run at full speed, without interfering with each other.

------------------------------

I should point out that there are two separate questions being asked / answered here. The question I answered was:

(1) Will both drives run at full speed, without interfering with each other? (Yes, they will run at full speed. If that is all you care about, then stop reading here).

------------------------------

The question you asked was:
(2) Does SATA-3 share bandwidth with M.2 PCIe?

That is a more complex question to answer. And it is a question that is 100% pure theory. In theory, yes. At some point, PCI and SATA share bandwidth. But In reality, you will never bottleneck SATA / PCIe by running two drives on both interfaces at once.

Both SATA and PCIe are interfaces that are controlled directly by the Intel motherboard chipset. The only time the data traffic between SATA and PCIe compete for any kind of bandwidth is the connection between the Intel Chipset <--> Intel CPU. On a modern motherboard Chipset, like Intel Z170 or H170, that connection happens over DMI 3.0, which has a maximum theoretical 4.0GBps bandwidth.

In order to have any kind of bandwidth conflict, you will need to run a transfer of over 4.0GBps. First of all, you simply cannot achieve that with a Dell XPS 15, because you cannot connect enough drives to the system that come close to hitting that limit. You would need multiple PCIe and multiple SATA-3 drives, all running at full speed, in order to achieve that.

Second, even if you did theoretically achieve a 4.0 GBps transfer speed (by using multiple drives), it will be done in completely artificial benchmark scenarios. In the real world, you will never run into this scenario. Because you need an actual source drive to feed data, and a destination for all of that data. It is pretty difficult to actually build any kind of computer with the drives it would take to bottleneck 4.0GBps. It's possible, but doing so would be done entirely to prove theory over synthetic benchmarks. You will not find any kind of desktop usage scenario that will ever possibly use 4.0 GBps.

Lastly, even if you did manage to somehow construct a system that has the hardware capable of exceeding 4.0GBps, and found a real-world scenario that actually uses 4.0GBps, you would never notice. OS, application, and game load times do not benefit much (if at all) from any kind of drive speed above SATA-3 (~550MBps max). Going to something like a Samsung 960 Pro M.2 PCIe (2000MBps read max, 1500 MBps write max), which is the fastest consumer drive you can buy, doesn't improve os, app, or load times. So going even beyond that to 4.0 GBps max wouldn't make a difference.

That leaves pure file transfers left. And again, remember that writing to a Samsung 960 Pro at 1.5GBps means that you need to have some data source that can read at 1.5GBps. And you can count on one hand the number of drives that are capable of doing that.

Again, the only time you would ever be able to try and saturate the 4.0 GBps bandwidth of DMI 3.0 would be if you intentionally built a system with hardware capable of doing that; intentionally created a data workload capable of doing that; and had some way to measure the difference. And if you take all of that together, you end up with a system with multiple PCIe and multiple SATA drives in it, running synthetic benchmarks, built for the sole purpose of benchmarking to measure or disprove theory.

So, back down to Earth
... Don't worry about it. Running a PCIe SSD and SATA-3 HDD in the same system will not slow each other down.








Sent from my SM-G935V using Tapatalk

 

Thanks Kent.

I think this assumes Dell engineers have not messed around with the 2.5" bay cable or bus. I would still like to see confirmation a SSD drive runs at full SATA3 speeds in that big bay.

Apple did that to a few of my (EDIT) SSD ports, crippling performance of swapped SSD drives (despite Apple's published hardware specs at the time). Well, Apple specs were technically correct the hardware could run at SATA2 speeds but Apple just chose to limit speeds artifically via firmware...

SuperDrives lol

 

Is anyone able to confirm that Dell does not limit the speeds via firmware?

 

It could also be a hardware limit (cable...)

 

Of course.

If you were to use a 2TB 7200 rpm 7 mm conventional hard drive then there is no need to worry as these drives already cannot achieve sata 3 speeds.