Why does the hash rate drops when adding GPUs?

[beastman]

Hi everyone,

I've just finish setting up the following rig;
* Win 10
* 2X Sapphire - Radeon RX 580 4GB NITRO+
* 2X Sapphire - Radeon RX 580 8GB NITRO+
* radeon-software-crimson-relive-17.8.1-win10-64bit-aug18 drivers
also tested with non-whql-win10-64bit-radeon-software-crimson-relive-17.9.1-sep7 and got same result
* PolarisBiosEditor-master one click bios patch

When I only use one GPU at a time I can oc and get 29Mh, but drops to 24Mh when I add more GPUs and can no longer oc.

Has anyone encountered this issue?

Thanks!

[Vann]

Have you set virtual memory to a mininmum of 16GB? Press the Windows-Logo + R Keyboard Shortcut and type sysdm.cpl to access the Advanced System Settings in Windows 10. Under Performance you can set the virtual memory size to at least 16 GB and rebbot for it to take effect.

[beastman]

Yes that was done in my initial steps before launching claymore v9.8, thanks.

Funny thing is this also happens with Ubuntu.

Does this have anything to do with drivers?