Discussion Relative performance of the same SSD on 4x4 and 3x4 slots ?

[Pimpom]

I benchmark most storage devices that pass through my hands, including those of others. I generally use CrystalDiskMark and HDTune so that the results are obviously not as accurately representative of real-world performance as rigorous tests done by sites like Tom's Hardware. Still, they're useful as approximate indicators.

I've accumulated records of tests I did on a couple of hundred HDDs, SSDs, thumb drives and memory cards over the years. One thing I've noticed is that ordinary (slow) SD cards and USB 2.0 thumb drives often do better on a USB 3 port than on USB 2.

I haven't had a chance to compare the relative performance of PCIe 3.0 SSDs on 4x4 with that on 3x4. Does anyone have data on this?
Conversely, does a good Gen4 SSD (specced for say 6-7000 MB/s) do better in a 3x4 port than a Gen3 drive (say 3500 MB/s)?

Obviously a 7000 MB/s drive will be limited by a 3x4 port and will be faster on 4x4, but that's not what this topic is about.

 

[Misgar]

When you were testing SD cards, did you use a USB2 card reader in a USB3 computer port to get slightly faster speeds?

Are you 100% certain that your "slow" SD cards had a maximum transfer rate lower than the maximum speed of USB2?

USB readers and hard disk caddies with UASP run faster if the computer's USB port also supports UASP (USB Attached SCSI Protocol). I suppose it's also possible that USB2 thumb drives might support UASP for faster speeds.

It's possible the USB2 port on your computer did not support UASP, but your USB3 port came with UASP enabled. Hence the faster read speeds even if you were using a USB2 card reader.

https://en.wikipedia.org/wiki/USB_Attached_SCSI

I still have a few ancient 2GB SD cards with transfer rates below 5MB/s, but my fastest cards read back at 190MB/s in a UHS-I Kingston FCR-HS4 reader. With a UHS-II reader I'd expect up to 280MB/s read.

https://www.lexar.com/product/lexar-professional-1800x-sdxc-uhs-ii-card-gold-series/

 

[Pimpom]

Thanks for your interest. But right now I don't have time to write a meaningful reply addressing the points you raised. Will be back later. Sorry.