Does it support PCIe 4.0?
In order to buy the best m.2 ssd for this iMac, I would like to know if this can support PCIe 4.0 or it's just the regular PCIe 3.0?
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I don’t recommend M.2 SSD’s in iMac’s. You should use the custom Apple SSD’s. Here’s a good guide The Ultimate Guide to Apple’s Proprietary SSDs
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That wasn't the question... But thanks, I guess.
The SSD blade slot is custom to Apple, so simply put it does not mesh with the M.2 PCI standards.
In the description of 1TB apple ssd says: "These drives use a proprietary Apple PCIe 3.0 x4 interface." So it means although it's apple custom blade, is based on the standard Gen3 PCIe x4. My question is if this new imac can support the Gen4 PCIe.
Lisandro - There is two aspects to this, the systems connector & the SSD drive.
The first is the fit, as Apple is doing its own thing it does not comply with the M.2 PCI interface which is still currently PCIe 3.0 (the M.2 standards working group has not addressed PCIe 4.0 within their M.2 interface).
The second the signaling per Apples own disclosure is equivalent to PCIe as you've noted. Apple has not identified or published their interface, so we don't know if it is able to support the newer PCIe 4.0 signaling.
Don't forget Apple has been moving to a different type of storage using a custom storage chip (T2) and driving the raw flash chips via it. This design has been proven to be much faster than PCIe SSD's
PCIe 4.0 is coming! Its just become approved as standard and will take a bit of time before products ship PCIe 4.0 vs 3.0 – Speeds and release date and the systems they will fit in to support them. Apple has not commented on what its plans are. As a reference the new Mac Pro has PCIe 3.0 slots!
I fear many people will buy products that are labeled 4.0 which are still limited to the older PCI 3.0 I/O interface. The standard is a bit muddy which seems to be the SOP these days across the other standards as well.
One of the things people get stuck on is raw data throughput. As an example buying the fastest car won't get you to work any faster than a car that meets the performance of the road. So if the road is 60 MPH that's the highest speed you can legally travel. To add to this if its rush hour the road may claim 60 MPH but you may not get any faster than 20 MPH. PC systems are no different!
The other aspect it the technology of the storage medium, in this case solid state. The flash chips used in SSD's are only so fast! So while the I/O standard is fast the storage is not! Which is one of the reasons Apple did their own thing with the T2 and direct access to the Raw flash chips. Think of it this way... Apple has leveraged HDD RAID methods down to the chip level. So far Apple is the only one doing anything like this. While you can setup RAID with SSD's this is still limited to the discreet controller per drive and you need to use larger SSD drives to get the best performance!
Only the Ryzen 3000 CPUs with the X570 chipset support PCIe 4.0.
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I just installed a WD SN850 nvme m2 SSD on my iMac A2116. Although the hard drive speed is super fast now but still lacks of full speed which SN850 offers 7000 mb/s but i can get 3500 out of it on my iMac. I guess the problem is with the compatibility of the main board (generation of the PCIe) which could be a bottleneck for this high-end SSD. Anybody can add a comment on it ?
It is more likely to be Gen3.
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@perry86 - You over bought !!
Apple has not intro'ed any systems with serviceable drives that supports PCIe 4.0.
At to using a M.2 SSD in your system you're taking a sizable chance! I strongly don't recommend them as I pull out quite a lot putting in the proper SSD's, either an Apple or OWC SSD.
If this was a MacBook Pro I would have less of an issue as its so easy to get in. iMac's are much more work and the expectation is heavier work loads.
