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October 31st, 2018 04:00
W/R SPEED - E5470 - NVMe Samsung 970 EVO
I just installed the Samsung 970 EVO on my Latitude E5470.
Based on my benchmarks my laptop is reading around 1720MB/s and writing 1500MB/s. However, it should be almost twice this values with this SSD. Seems like the speed is the same as if it was installed on a laptop that only supports M.2 PCIe 2.0.
Does it mean that the E5470 does not support M.2 PCIe 3.0? Should I change something in the BIOS?
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raf2222
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October 31st, 2018 10:00
Hello,
In the BIOS you should try to change from RAID mode to AHCI mode.
Also, you can get a "modded" nvme driver from winraid forum.
jphughan
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October 31st, 2018 19:00
Changing from RAID to AHCI won't change this. All it will do is prevent your OS from booting until you perform a clean install or change the setting back to what you had when it was originally installed. And a different NVMe driver is unlikely to make much of a difference either because you have a much larger bottleneck. There are two possible causes for what you're seeing:
- The system only has an x2 PCIe 3.0 interface to the M.2 slot rather than an x4 PCIe 3.0 interface.
- The system has an x4 interface but runs that interface in the power saving GT2 mode rather than max performance GT4 mode. This gives essentially the same performance as an x2 PCIe interface running in max performance. The XPS 13 9350 and 9360 work this way, for example.
With either of the above solutions, your maximum sequential read/write performance will be right around 1.8 GB/s, which is exactly what you're seeing, and even if your system uses the second design I mentioned, there are no user-configurable settings to change between GT2 and GT4. This has been widely discussed particularly with respect to the XPS 13 models I just mentioned.