Question about Rog Crosshair X870E Hero - PCIEX modes

[acare84]

Hello,

I want to purchase Asus Rog Crosshair X870E Hero motherboard my system but I need to learn something.

I read its manual and in the manual it is saying when you use both PCIEX16_1 and 2, both of them will run on x8 mode.

I have Sound Blaster AE5 Plus sound card and it is PCI EX 1 and I want to put that to 2nd slot. So my graphics card will run only on x8 mode?

I need to learn that before buying. Also I check Rog Strix X870E -E and it doesn’t have same problem because second PCIEX slot is 4.0 not 5.0. Maybe I should buy that.

Thanks for the replies.

[Silent_Scone]

Hi @acare84 

That's correct, when both slots are in use, they will split the lanes, resulting in the GPU running at 8x. The performance penalty for this is extremely marginal, however. Typically within 1-2% or less.