Well worst case I can just disect any 8i product and reverse engineer it. As long as I know where 3V and 5V is as well as the PCI-E lanes, I should be good. Requires me to blindly buy multiple 50$+ products though when besides these basic but expensive OcuLink 8i to Full sized PCI-E adapters nothing uses 8i - all off-the-shelf eGPUs use x4 (though if you’re in it for the lower price you’d want a PSU+x16 adapter+desktop GPU anyway
But about the 8i and eGPU: i mean i would just buy a 8i to pci-e board and connect it there (with a 8i to 2x 4i adapter). They are available on aliexpress but yeah, if you want not to build it by yourself it will always be 4i, yes
Heck yeah! Thanks, did not find it anywhere.
Rev 1.0 only includes x4, I think 8i (and the naming scheme change) was added later, presumably in Rev 1.1
But with that pinout we should be good!
Uploaded the OCuLink x4 adapter plate, refined it a bit more, as well as an improved template (added fan connectors, hopefully correct, and fixed some errors).
I tried to adhere to 19mm trace width 25mm pair spacing, which is kind of following what jlcpcb suggests for JLC04121H-3313 to get PCI-E compliant impedance - I think.
Also before sending it off I’d replace some of the 6mm holes with drill holes, right now they would be milled, not optimal
EDIT: Also, the 8i pinout implied the Vendor Position on the x4/4i were used for the PCI-E ref clk even though Rev. 1.0 didn’t specify that. Very good to know, so my current implemetation is probably not working
EDIT2: Sadly, it seems 8i is super hard to source. Seems to be only manufactured on demand, with MOQ of 4200, so unlikely to happen anytime soon. Weirdly no resellers, we do know some companies make products with them, but none of them seem to resell. If anybody finds a source, I might continue work on it
Oh no, I think that would be better. As one of the other clever types observed, if you can run dual 4i connectors you’re compatible with any other laptop on the market that uses a 4i-M.2 adapter! Much wider market potential.
Next stop would be producing a dock that can receive a pair of 4i connectors and be powered by a standard ATX PSU. Partnering with another guy who’s already making a dock might help, if you can work something out.
Good on you for having a go!
So what’s MOQ mean - is that a minimum order number, price to make one unit, or something else…?
Both the 8i and 4i pinouts are both publically accessible, I was planning on trying at least to make a dock. I have both 8i and 4i connectors in my inventory so I can do it.
With the existence of cheap 8i to dual 4i cables, it shouldn’t make a difference. Except, plugging in a single connector into your framework is easier than having to plug in two.
Not great resolution in this picture, but it doesn’t look like there is anything blocking that area.
You mean you need a female 8i or a male 8i or both? Because both is available on aliexpress.com as a cable. What i not find atm is a docking-station PCB with 8i oculink to PCI-e x16.
Could you please link a 8i to PCI-E 4.0 x16 Dock from aliexpress? I really can’t find it.
That’s sth i wonder. Is it technically in term of signal quality no loss? Because you go from PCI-E x8 to 2 times Oculink 4i and then you go from 2x 4i to 1x 8i and then you will go into the Docking-station PCB (oculink 8i female) and then it will convert to x16 PCI-E.
So many, many “convertions”. Will that be fine for signal quality ? Because PCi-E is not like USB, it is quite difficult.
Edit: But if it would be the same, i’m not sure what is better. 8i would be “cleaner”. On the other hand with two 4i ports and a 8i to 2x 4i adapter you could also go for 8i, while still beeing able (without an adapter) to use 4i Oculink eGPU docks on the market. But on the otherhand if you have an 8i and you want to use a 4i eGPU dock, you also just could buy a 8i to 2x 4i cable. Because there are already 8i docks on aliexpress (sure, only naked boards). So personally i would rather buy that than for example the one dock, which is less futureproof, because it has “only” 4i, which has already today 8% less perfomance on a 4090 according to techpowerup.
So im not sure what is better
It depends on who has to buy an adapter and what is acceptable to buy (a nice looking dook on the market, which are all 4i atm, or a 8i dock from aliexpress, which are only the naked board. But if you buy a dekstop-computer you are also able to look on a naked mainboard so…). And also if in future all docks will be 8i or if it never becomes a thing, if you don’t buy it by yourself on aliexpress.
At the end there is an adapter for both cases (actually it’s the exactly same adapter, just plugged in the other way around). So i mean for me, im fine if it is two 4i, but for sure i personally would preffer an 8i. But also, if it is way more difficult to make an 8i, i can understand not doing it, if one only had to buy an adapter. But on the other hand: 8i is better xD haha
Could you please link a 8i to PCI-E 4.0 x16 Dock from aliexpress? I
Here is one such dock 8i dock
I searched for “oculink dock” and scrolled a bit.
I don’t own this dock, so can’t speak for this particular product, but since the chinese have used that stuff for crypto, I trust them to make it work.
You mean you need a female 8i or a male 8i or both?
I think he needs a surface mounted connector to solder onto the PCB, not a cable.
Like this 4i one
Ahh nice, i couldn’t find it anymore, because i think i saw the exactly same dock some days ago. But good, now we have it here, if we don’t find it anymore.
Btw. you can quote by marking other users’ Text (if you are logged in) and then click on quote. Then you have the name in it and other users can go to the original post, when seeing a quote somewhere.
Edit: There is a 4i to 8i cable on Aliexpress. What i don’t understand is: Why is it only 16gbps *2 ? Is this meant per lane and *2 because of the y-cable? Because PCI-E 4.0 has per lane 16gbps. Also the 8i to 8i cable are rated for 16gbps.
@Seneral : So if we can help you, tell us. For me i am not able to help with pcb design for now, but maybe other things.
That ought to be fine. There are some mentions of capacitor for TX lanes, which I would like to incorporate in the final design, but assuming there are some in the framework themselves, it might work like this. There should be no difference to the 2x 4i or 8i solution here.
For me, it’s purely a question of practicality and expense.
8i seems harder to get, if at all, and 4i also means easier design of the PCB (routing becomes easier if you have a bit more space around each, especially for a beginner like me).
Yep 4i is easy to get cheaper on mouser even, 8i not so much. Sadly your 8i link seems to be broken.
Searching on aliexpress is impossible, for some reason I only get batteries and shower heads no matter what I try.
I’ll probably be redesigning the PCB for whatever solution we’ll come up with, 2x4i or 8i, plus I’ll try to include a Displayport connector for the internal screen. That is a LOT for me so I’ll try to get some advice from my friend.
So sourcing of connectors is my biggest concern.
Do you have the official specs for 8i? The connector pinout above leaves some room for interpretation. Also if you have a source of PCB-mounted 8i connectors, that’d be a great.
If you have concrete plans to redo an 8i to 16x design similar to what we can already buy, it might be good to work together so the designs can be ordered together (also because I’m not certain my impedances are good). Did you already pick a stack from a PCB manufacturer with known impedances? If so, what trace widths and spacing did you go for? As I mentioned before, I preliminarily picked JLC04121H-3313 with now 0.19mm trace width and 0.25mm spacing.
For the internal screen. So you can plug in one of your eGPUs outputs up to the back so the internal screen can run of the eGPU (among others, ofc). Much better than using the PCI-E bandwidth somehow to achieve the same
Btw. I also just made the decision to use epoxy-filled vias and ENIG coating, which increases the cost of the PCBs from laughably low to decently expensive (especially for small orders). One is invaluable in actually connecting up the many pads of the connector, I already had some trouble with just 4 lanes of PCI-E, epoxy-filled vias allow me to have vias under the pads. The other is a premium coating (basically gold on the pads) which should increase the lifespan of the connector (I assume the framework MB already has that so it would just be to match whatever lifetime expectancy they already have)
