Possible multi GPU issue

harvey3

Junior Member
Dec 28, 2017
4
0
1
Hello, I recently built a Threadripper PC:
AMD Ryzen Threadripper 1950X
Asrock X399 Gaming Pro motherboard
32 GB GSkill Flare X DDR4 3200 RAM
960 EVO 500 GB M.2 SSD
dual Seagate Ironwolf Pro 6TB hard drives in RAID 0
Zotac GeForce GTX 1080 TI Amp Extreme GPU
PowerColor Red Dragon Radeon RX 560
Raidmax RX-1000GH Vampire 1000 Watt 80 Plus Gold PSU
Thermaltake View 71 case
Sorry forgot to add the CPU cooler Enermax Liqtech TR4 240 AIO

I am running the 2.0 BIOS on the motherboard and everything works fine. I have the GTX 1080 Ti in the first 16x PCIe slot and the RX 560 in the second. The cards have separate monitors on them. Three for the GTX 1080 and one for the RX 560. All are 4k. The issue that I have is that when I am using the RX 560 at say 40 % that usage shows up in Task Manager under both the RX 560 and the 1080 Ti. It does not do this when using the GTX 1080 Ti.

Is this an issue with the relative slowness of the RX 560? Is it a Windows issue, or is it related to the way the motherboard allocates PCIe lanes?
I only added the RX 560 to have both Cuda cores and Stream processors for various programs that i use that can take advantage of one or the other. And the fact that the RX 560 does not use additional power connectors.
Should I ditch the RX 560 for a faster card like thew RX Vega 56?
 
Last edited:

aigomorla

Cases and Cooling Mod PC Gaming Mod Elite Member
Super Moderator
Sep 28, 2005
19,622
1,999
126
you really should not be using RX560 with a 1080Ti....
Nvidia Control Panel does not play nice with Catalyst Control Center.

Im sure the 1080Ti could handle 4 monitors... why are you running a RX560 with it?
 

harvey3

Junior Member
Dec 28, 2017
4
0
1
I only added the RX 560 to have both Cuda cores and Stream processors for various programs that i use that can take advantage of one or the other. This allows me to use programs optimized for either card. I have noticed that some tasks that are hardware assisted to not present this issue as much such as H.264 playback on a program that uses hardware acceleration.
BTW I have had no driver issues with this configuration and both the NVidia control panel and the AMD Radeon Settings panels work fine.
From what I have seen on other websites using a Vega 64 should solve this issue as it is at least as fast as the 1080 Ti. It is looking like the motherboard I am using shares the bandwidth from the two 16X slots. I think this is why the slower RX560 is showing up in the 1080 Ti.
It may be an option I can change in the BIOS I still have to look into that.
 

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