Aplicata Quad M.2 NVMe SSD PCIe x8 Adapter Review

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MRFS

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> Do I build a PCIe 3.x based system now with DDR-4, massive i9's or thread ripper processors and put one of these in, or do I wait for the speed advantage of PCIe 4 or 5?

I would recommend waiting a few weeks for Highpoint
to officially release bootable RAID support for their
model SSD7101, and for prosumers to report success
installing that add-in card in a TR system.

A prosumer at another Forum experimented and
found that the driver software for Highpoint's SSD7110
does work with the model SSD7101, but that success
was "unofficial" (for now).

The specs for the Highpoint SSD7101 also state that
multiple add-in cards can be installed in the same motherboard.

So, you can scale a Threadripper system now and obtain
the same bandwidth which you will get by waiting for
PCIe 4.0 to become widely available.

Also, of significant importance is the relatively large
number of PCIe 3.0 lanes which TR brings to the table:
you don't want your chipset lane assignments
to assign only x8 PCIe 3.0 lanes to an add-in card
that has an x16 edge connector.

Also, remember that both ends of a data cable
need to oscillate at the same high speed:
it may be a while before NVMe SSDs reach
PCIe 4.0's clock speed of 16 GHz.

Moral of this story: there are good reasons
to wait for the x16 add-in cards to mature
and for motherboard BIOS/UEFI subsystems
to be optimized for these leading-edge devices.
 

bit_user

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There's no answer for timing upgrades that's right for everyone. In my case, I have a Sandybridge-E workstation with PCIe 3.0 that's working fine, so I figure PCIe 4.0 might be a reasonable point for an upgrade. But, coming from an old Core 2, or even an i7 laptop, you're in for quite a step up with Kaby/Coffee Lake or Ryzen.

Unless you need lots of cores, I'd skip Intel's LGA2066-based CPUs. Maybe next generation will unlock more of their potential, but the thermal performance of the current generation means you won't be getting all the performance for which you'd be paying so much.

Threadripper is a promising option for high core-count applications and lots of PCIe lanes, but performance is a bit inconsistent. So, whether it makes sense depends a lot on what you plan to do with it.

Coffee Lake sounds tempting, but I'm currently using more PCIe lanes that it'll have, so I'd really rather wait and see if Intel's next generation of LGA2066 CPUs makes a better showing. That said, I'll probably just hold out for PCIe 4.0, unless something forces my hand.
 

joevt1

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How does this compare with the amfeltec gen 3 x16? How well do they work in a PCIe gen 2 slot? Does either product's bridge chip support PCIe gen 2 5.0 GT/s or do they fall down to PCIe gen 1 2.5 GT/s?
 

bit_user

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Are you aware of anything else that supports PCIe 3 and v1 but not v2? Just curious.
 

joevt1

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There are benchmarks at http://barefeats.com/hard220.html for the Amfeltec card that suggest that the four downstream ports of the bridge chip are 8 GT/s x4, but the upstream port is only 2.5 GT/s x16 in a PCIe slot that is supposed to support 5 GT/s x16.

I believe that the PCIe specification does not require a device to support all link speeds between 2.5 GT/s and the max specified link speed (8 GT/s in this case).

Four possibilities:
1) The bridge chip might not support 5 GT/s.
2) The 2010 Mac Pro chipset might not like the bridge chip.
3) The bridge chip might not like the 2010 Mac Pro chipset.
4) A combination of those last two.

Things that might be informative:
1) Some output from lspci command.
2) A datasheet for the bridge chip. All I can find is a product brief that says:
"PCI Express Base Specification, r3.0 (compatible w/ PCIe r1.0a/1.1 & 2.0)"
but that doesn't explicitly say that it supports 5.0 GT/s.
3) Tests in PC's with older chipsets that support PCIe 2.0 but not PCIe 3.0 - including a PC that has the same chipset as the 2010 Mac Pro.

I wonder if there's a way to force PCIe link renegotiation (in EFI or the OS) to get 5 GT/s working, if it is known that the bridge chip is supposed to allow 5 GT/s.
 
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