PCie to NVME card woes...


jbuszkie

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So I wanted to upgrade my cache and eventually make it raid 1.  I have two nvme slots but if I used the other slot on the MB I'd have to give up two sata connectors.  I didn't want to do that.  So I bought a PCIe 3.0 x4 card to NVME.

My MB has 3.0 PCIe so great I thought.

 

So I plug it into one of my non x16 slots and powered up.  

I ran the disk speed benchmark and I was unimpressed. Less than 1G/s  I ran the onboard existing NVME drive and it was 3x faster!  I'm like crap!  Are my slots not really 3.0?  Was there some limitation in the slot I used?  So I pull up the MB manual and it looks like I have 3x x16 slots (of which only one can be x16 other wise 2x 8x) the last x16 is only x4.  And I have 3x PCIe 1x slots.  Guess what I plugged my 4x card into...  Yes a 1x slot!!

 

So I opened up the case again and move the card over to the real x4 slot...  And BOOM!  3x-ish. the speed!

I have no idea why I though the little 1x slots were 4x???

 

I'm an idiot sometimes!! 🙂

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  • 3 weeks later...

I think there is a miscommunication between on one hand x4/x1 = the number of PCIe lane between the MB and the plugin card. It can be x1, x2, x4, x8 ,x16.

And on the other hand the generation (thus bandwidth) of said PCIE link. It goes from PCIe 1 to 4 actually but never is written 4x but Gen4 for example.

 

PCIe Gen3 x1 or PCIe2 x1 is OK, PCIe 3x x8 is weird an not easily to understand. PCIe 4x by itself is unclear, are you talking generation, nb of lanes ?

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