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Journeyman III
Journeyman III

R9 290 Crossfire pci lanes 2.0 8x/8x

Hello ,  i just wanted know if i am bottleneck with two r9 290 on pci express 2.0 8x/8x my mobo is GA-990-XA-UD3 rev 3.0 , cpu AMD FX 8350 OC @ 4.4ghz.

Due to the fact that my r9 290 have no crossfire bridge , i think of an bottleneck and i'm not sur , very sorry for my bad english i'm french but know you on this subject?

Thank you every for any response

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Big Boss
Big Boss

Re: R9 290 Crossfire pci lanes 2.0 8x/8x

Your CPU, motherboard and video cards are well balanced for gaming. You can rest easy with the rig.

I have a chart I am working on for a R9 Fury which runs fine even with PCI Express 1.1 x4 so do not worry with PCI Express 2.0 x8 slots.

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Esteemed Contributor III

Re: R9 290 Crossfire pci lanes 2.0 8x/8x 

Guru3D did a good article comparing PCIe 1.1 x16 to PCIe 2.0 x16 to PCIe 3.0 x16 with the nVidia GTX 980 last year at 2560x1440, which is about 20% faster than the R9 290, in both single and SLI setups. PCIe 1.1 x16 = PCIe 2.0 x8 = PCIe 3.0 x4 in terms of bandwidth. There is technically a "bottleneck" of sorts in SLI, but it varies from between near 0% in Firestrike to 20% in Thief, with an average result of about a 10% speed reduction, but even then the frame rate is well above 60.

PCI Express Scaling Game Performance Analysis review - Article - Guide - Review

TechPowerup last year did a PCIe 1.1 vs 2.0 vs 3.0 comparison with the FuryX, but sadly neglected to do a Crossfire test, but even if the additional burden of handling Crossfire via PCIe reduced the effective bandwidth to PCIe 2.0 x4 levels, performance reduction would still be less than 10% loss vs x16

https://www.techpowerup.com/reviews/AMD/R9_Fury_X_PCI-Express_Scaling.html

So don't worry about it.

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