43 Replies Latest reply on Apr 28, 2017 11:32 AM by tiberiusjonez

    Radeon RX 480 crossfire performance problem



      I'm a fresh owner of two ASUS Radeon RX 480 8GB STRIX OC. I have the problem that my gpu (when crossfire is enabled) isn't 100% utilized in games causing them to run on lower fps than a single card and worse than on benchmarks.


      When I'm using Heaven Benchmarks both gpus are used in 100% but in any game it won't causing them to lag ;/

      One exception is Assassin Creed Syndicate - on max settings it's running like champ (100% both gpu's) but when I lower the settings, my cards lower it's power too causing the app running on low fps.


      Here is the video with benchmark, he is playing on lower settings than me but both of his gpu's are 100% utilized:

      Assassin's Creed Syndicate | AMD RX 480 Crossfire | FRAME RATE | MAXED OUT (1080p) - YouTube


      In my case the gpu usage constantly jump like on one card is 10% and on other 20% ;/


      Here are specs of my pc:


      MotherBoard: ASUS M5A99FX PRO R2.0

      CPU: AMD FX-9590 4.70GHz

      PSU: Enermax 1350W Platimax

      HDD: Plextor 128GB 2,5" SATA SSD M6S Series

      SEGATE st4000dx001-1ce168 4 TB

      GPU: 2x ASUS Radeon RX 480 8GB STRIX OC

      RAM: 4x DDR3 GOOD RAM 8GB 1600MHz Play CL 10


      Few things I want to mention:

      • It's not CPU bottleneck (all cores are below 70%)
      • I have a good PSU (1350W)
      • Drivers are up to date (I'm using latest Crimson 16.12.1 driver )
      • I tried to reinstall drivers like 50 times and the result is still the same (I tried clear install - same result)
      • Benchmarks utilize both gpu's giving me nice scores
      • AC Syndicate nearly double it's performance when using cf and max settings in game, but as soon as I lower the settings I have less fps than playing without cf enabled


      Rly pls help, I tried to post about my problem here:



      But they didn't give me answer to my problem.

        • Re: Radeon RX 480 crossfire performance problem

          Is AC Syndicate the only one game with this problem?

          Don't use 16.12.1  It has too many problems. Try 16.11.5

          Try to disable ULPS via registry editor and reboot after that

          1) Click Start - Type regedit.exe and hit enter.

          2) In reg editor, press F3 and type EnableULPS, hit enter.


          3) Keep pressing F3 until it finds a key called EnableUlps in a sub folder called 0000

          4) Double click the reg entry and change value from 1 to 0.


          5) Keep pressing F3 until it finds a key called EnableUlps in a sub folder called 0001

          6) Double click the reg entry and change value from 1 to 0.

          • Re: Radeon RX 480 crossfire performance problem



            I still can't find where is the problem. Yesterday I installed Crimson 16.12.2 but it didn't help ;/

            • Re: Radeon RX 480 crossfire performance problem

              Here's my results of heaven the card clocks are at stock 1303 core 2000 mem +50 power +48mv using MSI Afterburner, So as for my previous post I found out there is no way to go over 1.175mv using wattman but using afterburner you can set the mv +100 if you want. What's your heaven score can you post a screenshot of score and gpu-z just like this click the numbers on gpu-z to show max for core,mem,load,power draw,vddc I ran the test using extreme 1080p full screen 8xAA.


              1 of 1 people found this helpful
                • Re: Radeon RX 480 crossfire performance problem

                  Here are my msi afterburner settings:


                  I don't know how to unlock core voltage (mV).


                  Here is my bench:


                  Here are graphs after benching:

                  second gpu


                  first gpu:


                  And here is my max:




                  What I have noticed is that my second gpu temp is showed very very hot however I have open case and when I touch second card it's a lot more cold than the first one lol. It's something wrong with sensors I think. Second gpu is throttling to 1260 Mhz I don't know why(propably becouse of wrong sensors). It's voltage is also read wrong:



                  Thanks for help I will do a fresh Windows install in 2 months from now, maybe faster.

                • Re: Radeon RX 480 crossfire performance problem

                  I just wanted to tell you I tested AC: Syndicate on my rig FX 8370 @ 4.8Ghz Crossfire RX 480 all other games work great when people say there is a cpu bottleneck well the cores aren't reaching 100% on the cpu for some reason this game just hammers the temps like no other game. I also tried with the windows 10 game mode enabled in the newest insider build and it doesn't seem to have any effect on cpu usage like other games do. Also noticed when the temp reaches 60 it thermal throttles my cpu cores for a second to keep temps under 60 try to monitor your core speeds while testing again cause in the hwmonitor pic above i noticed your temp reached 60 and and your current core speed is less than your max speed.

                  • Re: Radeon RX 480 crossfire performance problem

                    Your motherboard is power throttling your gpu. Your motherboard only has 2x pci express 2.0 x16 it wont supply your gpu with enough power to run all of the operations efficently.


                    They are not getting enough power, my solutions.


                    1: Lower your gpu core clock in wattman so your gpu uses it wattage for more important operations. Don't be afraid of downclocking, as most crossfire settups have to do this to run more efficently. In firestrike ultra, the best benchmark had a build of 4x titan x all down clocked. Your shaders amount on your gpus being fully utilized will more than make up for the fps you lost from downclocking. you will get a net positive amount of fps.


                    2: get a motherboard with 2x pci express 3.0 x16 slots, and you will probably still have to downclock to not power throttle, just down clock less.


                    PLEase try option 1 first. Try soemthing like 1000mhz first on a crossfire supported game.

                      • Re: Radeon RX 480 crossfire performance problem

                        Well when I play Rise of Tomb Raider my cards are both in 100% usage with 180 - 200W power draw. So I don't think mobo is the problem. So far now I play Shadow of Mordor on full settings and get constant 100+ fps. However when I lower the settings I get stuttering lags etc.

                          • Re: Radeon RX 480 crossfire performance problem

                            wait, stuttering? That is a problem only with cpu and ram speed bottleneck. We know your cpu is going to botteneck your system at a certain fps, like your cpu may only be able to output like 90-120 frames max regardless of graphics settings.


                            WHich in your case just make sure you put on beefy graphics settings because you may as well.


                            Do you know what your ram speed is at? if you have a program called cpu-z open it, click on the memory tab. look for your ram speed(it is in mhz) and tell me.  I will tell you if your ram speed is fast enough(ram speed can serverly bottleneck your cpu, causing it to lose up to 50% of its true performance depending on how slow the ram is.)

                              • Re: Radeon RX 480 crossfire performance problem

                                My ram speed is 1600 Mhz. In Rise of Tomb Rider with dx12 I have both very high cpu usage as well as very good fps and 100% utilization on both gpus. The same Scenario is with far cry 4 and Shadow of Mordor.


                                But in games that use crossfire even if the cpu usage is like 5% I have stuttering, lags and very low fps ex 20 avg when on single card I have 80. So that is the reason that I don't believe it's the cpu bottleneck. Also heaven benchmark is using more cpu than every game I play yet I have 97.2 average fps on max settings 1080p.



                                  • Re: Radeon RX 480 crossfire performance problem

                                    1600mhz ram for a crossfire set up? 1600mhz barely provides enough for a single gpu and cpu nowadays. 1600mhz will make your cpu work 2 times as hard to make up for the poor bandwidth your ram provides. Hence the perplexing high cpu usuage on some of your benchmarks.


                                    Upgrade your ram to 8gb ddr3 2400mhz ram, make sure your mptherboard is able to overclock your new stick of ram to that amount or 2100.  The 2400mhz ram provides more memory bandwidth for your gpu and cpu removing stutters as the memory controller will often exceed the limit your 1600mhz bandwidth provides.


                                    In crossfire set ups you usually prefer ramspeed over latency because you need the extra bandwidth. getting ddr3 2400mhz ram will solve your problem with stuttering. On ne egg you can get cast 10 2400mhz ram which has good latency and enough memory bandwidth.

                            • Re: Radeon RX 480 crossfire performance problem



                              Ok, so glad I found this thread. Couple observations. First I don't have a solution, but together we may come up with one. In addition to the crossfire performance issues you've noted, which I've also has with 2x Asus Strix ROG 8GB RX 480's, I also cannot seem to select any resolutions in game above 1080p, even though I have enabled VSR at 1440p, and as high as 4k. I used to be able to...but can't any longer, and I'm not sure when the problem began.


                              I've tried rolling back drivers to ones that I knew worked, uninstalling Trixx, then GPUTweak, Then Radeon Settings, and disabling/enabling scaling. So far, nothing has worked. I'm flummoxed. I'm going to try the ULPS thing, but I don't expect it to work.


                              I was also interested in trying custom resolutions in an attempt to see if I could see what an ultra-wide resolution might look like on my 40" display, but attempts to try that only result in a really tall resolution that is not wide at all... very strange.


                              Win 10 64 bit Creators build

                              16gb Ram


                              2x RX 480 8GB


                              I have a new Ryzen PC (waiting for MOBO to arrive Monday) in the works, which will be built next week, so perhaps this will all solve its self with that... we'll see.