With oculink you are pretty much eliminating the bandwidth bottleneck if not reducing it to an extremely low margin. TB4 still holds gpu performance back sunstantially.
Basically, two things.
USB4 : worse performance (15-60% hit), most of the time plug in and play.
Oculink: Not plug in and play. Better performance (5-8% hit for PCI-E 4.0 x 4; 15-30% for PCI-E 3.0 x 4, 4.0 vs. 3.0 is determined by chipset.)
USB 4.2 and Thunderbolt 5 are supposed to give us the best of both worlds, but they are likely releasing next year.
also USB4 provides power delivery whereas Oculink only supports data transfer so charging your device while using an eGPU will require 2 cables with Oculink
You could, though the chances are slim, have PCIe 5
I only point this out because I built a 12th gen i9 in a Z790 board for a buddy. His PCIe 4 NVMe drives were faster than rated, so I built one with a i9 13900 and 3 NVMe SSDS to get close to 20GBps read and writes, so I'm curious how an occulink would work when it has way more bandwidth available. I mean, on a single drive performance of a Samsung 980 EVO Pro rated at 7500/7500, and I'm getting 8000/7900 I can help thinking the CPU lanes give us more than really advertised.
I bought a mini PC with a Ryzen R7 7840 and PCIe 5. I'm not going think I can run my 4090, but I think it'd do well with an RX7800 XT
Oculink is basically like using an NVMe based eGPU setup but with a detachable cable. It will have the same limitations of such a connection unless companies who build it into their systems take steps to solve some of them.
USB4 is more user friendly but there is a performance penalty that comes from having to ‘massage’ the PCIe traffic into a format that works over a USB4 cable then convert it back to PCIe on the other end.
Not really. There are many PCI to Oculink adapters. Even with 8 lanes. Two bad these are for desktop computers so it doesn't make too much sense to use it for an eGPU when you can plug it directly.
One of the best Gaming MiniPC's out with OcuLink as of 7/1/2024
Tiny and a mean little gamer rig with the eGPU. It has both USB4 and Oculink onboard.
# MINISFORUM Mini PC UM780 XTX AMD Ryzen 7 7840HS,8C/16T, 64GB DDR5 1TB PCIe SSD
[https://www.amazon.com/MINISFORUM-7840HS-Desktop-HDMI2-1-Stylish/dp/B0CPSFQPV6/?\_encoding=UTF8&pd\_rd\_w=ryb0x&content-id=amzn1.sym.3c3990c3-513c-4686-8d92-a42b4095cecb%3Aamzn1.symc.8b620bc3-61d8-46b3-abd9-110539785634&pf\_rd\_p=3c3990c3-513c-4686-8d92-a42b4095cecb&pf\_rd\_r=4A2S0WH5NFNF8WYVGPRW&pd\_rd\_wg=HzSSh&pd\_rd\_r=283a1c25-b00f-4967-936e-a66270c703b7&ref\_=pd\_hp\_d\_btf\_ci\_mcx\_mr\_hp\_d&th=1](https://www.amazon.com/MINISFORUM-7840HS-Desktop-HDMI2-1-Stylish/dp/B0CPSFQPV6/?_encoding=UTF8&pd_rd_w=ryb0x&content-id=amzn1.sym.3c3990c3-513c-4686-8d92-a42b4095cecb%3Aamzn1.symc.8b620bc3-61d8-46b3-abd9-110539785634&pf_rd_p=3c3990c3-513c-4686-8d92-a42b4095cecb&pf_rd_r=4A2S0WH5NFNF8WYVGPRW&pd_rd_wg=HzSSh&pd_rd_r=283a1c25-b00f-4967-936e-a66270c703b7&ref_=pd_hp_d_btf_ci_mcx_mr_hp_d&th=1)
That's a really broad question. A lot!
What's the similarity between USB4 and Oculink?
* OCulink is a connector and cable for 4x PCIe lanes https://www.delock.com/infothek/OCuLink/oculink_e.html
* USB4 may tunnel PCIe https://www.usb.org/sites/default/files/USB4%20Specification%20June%202023.zip
Generally USB4 has a lot more features, is a lot more complex, more expensive and for egpu use may have bigger overhead. Also not every USB4 port supports PCIe tunneling, which you need for egpu.
You may be able to power the computer through the USB4 port, which you can't do through OCuLink and USB4 is arguably a more convenient solution if you want to connect/disconnect regularly.
you have to disable/enable it in device manager every time you plug/unplug at least from my experience. Performance is drastically better with oculink compared to USB4
No graphics card is plug and play without setup, you have to install drivers. I think what they meant was can you just plug in/unplug oculink like usb4/thunderbolt without having to shutdown the computer. The answer is no because you’ll be greeted with a bsod.
> I thought all USB4 were compatible...
Unfortunately support is optional.
> How can I know if a USB 4 port is compatible with EGPU?
You mean before you buy? Read the product (motherboard, CPU) description, read the manual, ask the seller, message manufacturer's support.
PS: All Thunderbolt 4 ports have guaranteed USB4 PCI tunneling support. So if you see the Thunderbolt 4 logo you can stop researching.
Thunderbolt 5 isn't released yet so nobody knows for certain. But 99.9999% sure Thunderbolt 5 is going to have higher *hardware* requirements than TB 4.
Thunderbolt 5
What It Does: Thunderbolt 5 will deliver 80 gigabits per second (Gbps) of bi-directional bandwidth, and with Bandwidth Boost it will provide up to 120 Gbps for the best display experience
Considering PCIe is 160 Gbps, I'm thinking the actual loss in GPU performance is about as negligible as PCIe x8 vs x16.
I'd be a guinea pig and test it, but no devices yet.
With oculink you are pretty much eliminating the bandwidth bottleneck if not reducing it to an extremely low margin. TB4 still holds gpu performance back sunstantially.
a gpu that uses 8 pcie lanes normally. Assuming it can run through Oculink with 4 lanes. What sort of performance difference will be seen?
Basically, two things. USB4 : worse performance (15-60% hit), most of the time plug in and play. Oculink: Not plug in and play. Better performance (5-8% hit for PCI-E 4.0 x 4; 15-30% for PCI-E 3.0 x 4, 4.0 vs. 3.0 is determined by chipset.) USB 4.2 and Thunderbolt 5 are supposed to give us the best of both worlds, but they are likely releasing next year.
also USB4 provides power delivery whereas Oculink only supports data transfer so charging your device while using an eGPU will require 2 cables with Oculink
How do you know if your laptop has a PCI-E 4.0 x 4 m.2 slot or a PCI-E 3.0 x 4?
The chipset. If it is 11th Generation Intel or later, or 6xxx Ryzen or later.
okay cool! I got a 12th gen chip so we good thank you :)
You could, though the chances are slim, have PCIe 5 I only point this out because I built a 12th gen i9 in a Z790 board for a buddy. His PCIe 4 NVMe drives were faster than rated, so I built one with a i9 13900 and 3 NVMe SSDS to get close to 20GBps read and writes, so I'm curious how an occulink would work when it has way more bandwidth available. I mean, on a single drive performance of a Samsung 980 EVO Pro rated at 7500/7500, and I'm getting 8000/7900 I can help thinking the CPU lanes give us more than really advertised. I bought a mini PC with a Ryzen R7 7840 and PCIe 5. I'm not going think I can run my 4090, but I think it'd do well with an RX7800 XT
damn bro this is what I needed to hear thanks!
Oculink is basically like using an NVMe based eGPU setup but with a detachable cable. It will have the same limitations of such a connection unless companies who build it into their systems take steps to solve some of them. USB4 is more user friendly but there is a performance penalty that comes from having to ‘massage’ the PCIe traffic into a format that works over a USB4 cable then convert it back to PCIe on the other end.
Not really. There are many PCI to Oculink adapters. Even with 8 lanes. Two bad these are for desktop computers so it doesn't make too much sense to use it for an eGPU when you can plug it directly.
An eGPU setup is never NVMe based.
A bit late but not sure why you got downvoted. NVMe is a storage standard that often run on M2 PCIE. Parent post probably meant M2 PCIE.
So many people confuse NVME and M.2 / U.2 etc. NVME is a protocol it can run on literally anything…fibre channel, FCoE, pci express, etc,
One of the best Gaming MiniPC's out with OcuLink as of 7/1/2024 Tiny and a mean little gamer rig with the eGPU. It has both USB4 and Oculink onboard. # MINISFORUM Mini PC UM780 XTX AMD Ryzen 7 7840HS,8C/16T, 64GB DDR5 1TB PCIe SSD [https://www.amazon.com/MINISFORUM-7840HS-Desktop-HDMI2-1-Stylish/dp/B0CPSFQPV6/?\_encoding=UTF8&pd\_rd\_w=ryb0x&content-id=amzn1.sym.3c3990c3-513c-4686-8d92-a42b4095cecb%3Aamzn1.symc.8b620bc3-61d8-46b3-abd9-110539785634&pf\_rd\_p=3c3990c3-513c-4686-8d92-a42b4095cecb&pf\_rd\_r=4A2S0WH5NFNF8WYVGPRW&pd\_rd\_wg=HzSSh&pd\_rd\_r=283a1c25-b00f-4967-936e-a66270c703b7&ref\_=pd\_hp\_d\_btf\_ci\_mcx\_mr\_hp\_d&th=1](https://www.amazon.com/MINISFORUM-7840HS-Desktop-HDMI2-1-Stylish/dp/B0CPSFQPV6/?_encoding=UTF8&pd_rd_w=ryb0x&content-id=amzn1.sym.3c3990c3-513c-4686-8d92-a42b4095cecb%3Aamzn1.symc.8b620bc3-61d8-46b3-abd9-110539785634&pf_rd_p=3c3990c3-513c-4686-8d92-a42b4095cecb&pf_rd_r=4A2S0WH5NFNF8WYVGPRW&pd_rd_wg=HzSSh&pd_rd_r=283a1c25-b00f-4967-936e-a66270c703b7&ref_=pd_hp_d_btf_ci_mcx_mr_hp_d&th=1)
I wish I had the spare income and time to try and do a solid comparison of these two different sets of technology.
That's a really broad question. A lot! What's the similarity between USB4 and Oculink? * OCulink is a connector and cable for 4x PCIe lanes https://www.delock.com/infothek/OCuLink/oculink_e.html * USB4 may tunnel PCIe https://www.usb.org/sites/default/files/USB4%20Specification%20June%202023.zip Generally USB4 has a lot more features, is a lot more complex, more expensive and for egpu use may have bigger overhead. Also not every USB4 port supports PCIe tunneling, which you need for egpu. You may be able to power the computer through the USB4 port, which you can't do through OCuLink and USB4 is arguably a more convenient solution if you want to connect/disconnect regularly.
You can't just plug and play with a OCulink?
you have to disable/enable it in device manager every time you plug/unplug at least from my experience. Performance is drastically better with oculink compared to USB4
That hotplugging/hotswaping, "plug and play" just means it works when you plug it in with no setup.
No graphics card is plug and play without setup, you have to install drivers. I think what they meant was can you just plug in/unplug oculink like usb4/thunderbolt without having to shutdown the computer. The answer is no because you’ll be greeted with a bsod.
For me it's been plug and play....the difference lies in having to modify the bottom case to allow the cable connection.
How can I know if a USB 4 port is compatible with EGPU? I thought all USB4 were compatible...
> I thought all USB4 were compatible... Unfortunately support is optional. > How can I know if a USB 4 port is compatible with EGPU? You mean before you buy? Read the product (motherboard, CPU) description, read the manual, ask the seller, message manufacturer's support. PS: All Thunderbolt 4 ports have guaranteed USB4 PCI tunneling support. So if you see the Thunderbolt 4 logo you can stop researching.
Is Thunderbolt 5 a hardware change from Th4 or just software? Genuinely curious
Me 2
Pretty sure it’s a software change if you’re just talking about PCI-E. I don’t think gen 5 is out of PCI-E yet.
Thunderbolt 5 isn't released yet so nobody knows for certain. But 99.9999% sure Thunderbolt 5 is going to have higher *hardware* requirements than TB 4.
Do you think it might have 8 lanes instead of 4? That would be very good for performance.
Yes. It will have 64Gb/s PCIe tunneling bandwidth vs the 32Gb/s it has right now.
Thunderbolt 5 What It Does: Thunderbolt 5 will deliver 80 gigabits per second (Gbps) of bi-directional bandwidth, and with Bandwidth Boost it will provide up to 120 Gbps for the best display experience Considering PCIe is 160 Gbps, I'm thinking the actual loss in GPU performance is about as negligible as PCIe x8 vs x16. I'd be a guinea pig and test it, but no devices yet.