5 Replies Latest reply on Apr 4, 2017 6:45 PM by jgi

    rx 480(pci3.0) performance issues on pci2.0 motherboard?

    jgi

      Hi I bought a gaming pc from a company who put it together for me.

      Specs: When I first bought it: 2x Radeon R9 390 8GB, msi 970 gaming, amd vishera fx-8350, 850W Cooler Master V850series, corsair hydro h100i, 32GB DDR3 RAM, 500GB SSD,                                                                         asus xonar DGX, windows 10 home

                  Now: Since the 2x Radeon R9s broke it has 2x RX480s which are now broken as well they only lasted about a weak...

       

      I've had performance issues since the beginning with the R9s, with the R9s ist wasn't so bad lower frame rates then expected but as long as I kept or reinstalled the oldest radeon drivers nothing really bad.

      After about 6 months both the R9s were broken, I returned the pc as it was still under warranty and it came back with 2 RX 480s.

      With the RX480s performance was horrible frame rates averaging at best 30fps with the worst drops to 7fps

      .

      Both the R9 and the RX480 need pci3.0 ports for best results but they should still be able to run on pci2.0 ports however this could result in a bottleneck because pci2.0 is slower, according to this post especially if you have multiple according to this post PCI Express 3.0 x16 graphic card on PCI Express 2.0 x16 slot? - [Solved] - Graphics Cards.

       

      Is this maybe the source of all the performance issues I and probably some others have been experiencing, the fact that under a higher workload the RX480, R9 and other newer pci3.0 gpu are simply incompatible with older pci2.0 motherboards?

      I certainly think so because my R9s performed better and lasted longer because their older design requires them to be connected with a cable which should reduce the workload on the pci ports, while the RX480s don't need to be connected plugging them to the motherboard and power supply should be enough, but only being connected with the motherboard will result on a higher workload on the pci ports so it seems logical that RX480 performed worse and lasted only a week vs 6months for the R9.

       

      I hope someone could confirm if this is the cause of all of my problems and broken parts.

      Or if you are experiencing similar issues and you also have 2 pci3.0 gpus on a pci2.0 motherboard you could check if it actually increases performance when you remove one of them, then we would be sure...

        • Re: rx 480(pci3.0) performance issues on pci2.0 motherboard?
          jgi

          found this one seems to point in the same direction

          Does RX480 fail PCI-E specification?

          • Re: rx 480(pci3.0) performance issues on pci2.0 motherboard?
            ibanggpu

            your gpus are being power throttled. pci express 2.0 is designed to only run one of the modern gpus.

             

            pci express 3.0 is better at this. But I would consider running only one rx 480 or upgrading your motherboard.

             

            I mean with two rx 480 it seems like you are trying to run your own universe.

              • Re: rx 480(pci3.0) performance issues on pci2.0 motherboard?
                jgi

                Thanks for confirming this, the company which I bought it from has agreed that the motherboard is the source of the problems I can send it back they will replace all broken parts and put in a motherboard that is capable of supporting all the other parts.

                  • Re: rx 480(pci3.0) performance issues on pci2.0 motherboard?
                    ibanggpu

                    Also dont be afraid to down clock your gpu when you are running a crossfire setup to ensure each of your gpus are getting enough power.

                     

                     

                    If each are getting enough power, the double amount of steam processors and tmus performance increase will outnumber the performance you lost from down clocking your gpu.

                     

                    The best build in the 3d mark firestrike ultra hall of fame  has 4x gtx titians which are all downclocked and not overclocked so esch of them get enough power to not throttle.

                      • Re: rx 480(pci3.0) performance issues on pci2.0 motherboard?
                        jgi

                        Well my pc is back and so are the problems, stability improved after clocking down, but not enough it still crashed and by now I'm pretty sure there is hardware damage. So I've asked my money back.

                         

                        So if you had a budget of about 2600€ to build a high-performance gaming pc what would you put in and how would you tune it?

                        It's main feature should be that it is able to play the newest games with their graphics set to max 24/7 and this in even in a hot room.

                        I mean I'm a human being I really think that when it comes to gaming I should break down or give in before my computer does because IT'S A MACHINE.

                        It should laugh at me for not being able to stay up for more than 72 hours in a row or for not being able to properly regulate my body temperature when the room temperature goes above 30 degrees Celsius.