5 Posts
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946
Inspiron 14 5485 2in1 PCIe NVME Speeds
After feeling like the included Toshiba BG3 128GB NVME SSD was a little too small for me, I purchased a new Pioneer 256GB NVME SSD to replace it with. Couple this with the fact that it 'felt' slow to me. I benchmarked it and it was maxing out at 500MB/sec read and 420MB/sec writes. That's slower than a good SATA SSD! But, whatever, its an included SSD. I imaged the stock SSD to an external drive, swapped out and restored the image to the new drive. No issues at all.
I immediately benchmark the new drive, rated @ 3200MB/sec read and 1800MB/sec write and .... 1200MB/sec read and 600MB/sec writes. Strange... so I threw the drive into my desktop and it benched at 2900MB/sec read and 1600MB/sec writes. Brilliant, so the issue isn't the drive. I put it back in the laptop, boot up and run CrystalDisk Info which tells me that the drive is only operating at PCIe 1.0 x4 speeds, but the drive supports PCIe 3.0 x4 speeds. I updated NVME and chipset drivers, I loaded the latest BIOS, checked in the BIOS and there's zero configuration options that would do anything at all.
Has anyone else run into this issue?
icase81
5 Posts
0
August 21st, 2020 07:00
This is 100% a BIOS bug. I downgraded from 2.5.0 back to 2.1.0 and the issue has (sort of) gone away. I still get a drop from 3300MB/sec to just shy of 900MB/sec when on battery, but now it goes back to full speed once I'm on the charger again. All of my random reboots around power and sleep seem to have been resolved as well. BIOS 2.5.0 seems like a dud for my particular laptop.
icase81
5 Posts
0
July 30th, 2020 12:00
More info:
CrystalDiskMark says it's @ PCIe 1.0 speeds, but that can't be true. PCIe 1.0 x4 tops out at a max of 1000MB/sec and I seem to have a cap around 1200MB/sec no matter what benchmark I run. Something seriously funky going on here.
jphughan
4 Operator
4 Operator
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14K Posts
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July 30th, 2020 13:00
@ejn63 Even if the interface is GT4, it still shows up as PCIe 3.0 x4.
@icase81 I've seen multiple cases on this forum where people got slower than expected PCIe interface negotiations and they were resolved by simply removing and reseating the NVMe SSD in the M.2 slot. I wouldn't have thought that connector had much "wiggle room", but evidently it does, because I've personally suggested this to at least 4 people on this forum and it solved their issues. One person had to try it twice before getting PCIe 3.0 x4. But to ejn63's point, if your system is set up for GT2 mode, then your max transfer rate will be around 1.8 GB/s, since an x4 interface in GT2 mode is roughly equivalent to a PCIe 3.0 x2 interface.
ejn63
10 Elder
10 Elder
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23.7K Posts
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July 30th, 2020 13:00
Most Inspirons ship with the NVMe/PCIe X4 set in GT2 power saving mode. That means the maximum you'll see is 1800 M/s.
Newer, higher-line models (XPS) have implemented GT4, as have gaming systems - but your Inspiron is almost certainly GT2, which will limit what you get from even a fast NVMe drive.
icase81
5 Posts
0
August 9th, 2020 13:00