Gen4. Nope.

I don't think they be that much different between gen 3 and 4 there already a gen 4 GPU out on the AMD side and it's not really much gain so i wouldn't run out and grab a gen 4 mobo unless you were already upgrading.

kram36
It's Gen 4.
 
We'll have to see benchmarks to know if any performance is being left on the table running the cards in Gen 3 mode, but Digital Foundry has benchmarks of the RTX 3080 on Gen 3 and the card does very very very very well.
 

Heck freakin yes! I know corporations always advertise or present their absolute "best" and cherry picked numbers, but I'm so glad to see that these numbers don't seem like they're cherry picked. I'm even MORE excited for these graphics cards than I was before!

Gen3 should be more than enough PCIE bandwidth for most scenarios.

MatthewAMEL

Sajin
Gen4. Nope.

Gen4 is right. And you absolutely will be constraining the card if it's on Intel.
 
Games like Horizon Zero Dawn already show a 10% difference in frame rate using a 5700XT on Gen3 vs Gen4.
 
Go check out Hardware Unboxed comparison last week between 5700XT and 2080Ti using Gen3 and Gen4. It's significant.
 
I'd post the video here, but I'm not allowed.

There are a ton of other reasons why AMD is outperforming Intel on Decima engine games and it has nothing to do with PCIe 3 vs PCIe 4.  The Decima engine scales with threads.  You can also see it in Death Stranding benchmarks too as they increase the threads up to about 24.  Just watched the hardware unboxing and it showed no difference/1 frame rate on all but the 2 Decima Engine games.  DS had a 4% difference and HZD was 2% (not 10%)

MatthewAMEL
 
 
HZD was 5% on the 5700XT between Gen3 and Gen4. 5% on F1, 13% in Wolfenstein:Youngblood, 5% in Death Stranding.
 
They simply went into the BIOS and switched Gen4 off. The Decima benchmarks were already running on AMD. So more threads was already factored into the numbers.
 
If it's that big a delta on a card that is half as fast as a 3080...imagine what that will look like a year from now when more and more games are using the Gen4 bandwidth. When developers really start to leverage RTX IO (NVCache) you will easily need the Gen4 pipe.
 
The best way to answer the question, IMHO, is 'you are losing ~5% of a 3080's performance on current gen games. Potentially much more with next gen games'.

What are you talking about?  Are you watching the same video?  You told me hardware unboxed https://youtu.be/PAwIh1nSOQ8
 
HZD largest difference was on 1080P.  It went from 133 to 137.  That is 3%.  And it goes to literally the same at 4k.   F1 has a 3 frame rate difference at 1080P and 1440.  The larger % would be at 1440P since a lower frame rate.  124 to 127.  That is a 2.5% difference.  Wolfenstein is literally 1 frame, which is under 1%.  Death Stranding goes from 140 to 145 for 3.5% at 1080P.  I have no idea where you are getting these 10% from HZD, like you originally stated, or the 13% from Wolfenstein.  All of those are within margin of errors too, meaning you could do the test multiple times and it might show less than 1% at times too.