ETH Hashrate drop on Polaris 8GB cards?

[bobben2]

Guys,
I have a rig with RX 470 8GB cards mining ETH and they were running at around 30MH/s each, but today I noticed a drop in hasrate to around 29-29.5  on all of them.   Surely, they should not be affected by the increased DAG size yet?  Any of you noticed the same?
The current driver version is 18.5.1.   All cards are BIOS modded.   I wonder if a higher driver version will bring hashrate back up to 30?
I already checked ping rates and they are unchanged.
EDIT: I am using Phoenixminer 5.1c

[Wingsbtc]

Maybe DAG File size already increase again, no sure though but try changing miner first to find out, your graphics card is 8gb memory, the DAG size isn't close to 8gb yet so I don't suspect the DAG File size in this case, what type of miner are you using? Is it up to date?

[Andor9505]

Use the latest Poloniex miner :https://mega.nz/folder/aUkFFYJB#6ftCtrJ5YMijIHAkFTK7Fg
Driver 19.3
-No Bios mod
-rxboost 50
-mt 1
Write in private if I can help.

[P00P135]

Use the latest Poloniex miner
Driver 19.3
-No Bios mod
-rxboost 50
-mt 1
Write in private if I can help.

Don't download anything from random people on the internet.

[hustleman]

Guys,
I have a rig with RX 470 8GB cards mining ETH and they were running at around 30MH/s each, but today I noticed a drop in hasrate to around 29-29.5  on all of them.   Surely, they should not be affected by the increased DAG size yet?  Any of you noticed the same?
The current driver version is 18.5.1.   All cards are BIOS modded.   I wonder if a higher driver version will bring hashrate back up to 30?
I already checked ping rates and they are unchanged.
EDIT: I am using Phoenixminer 5.1c

Not the same cards but both my RX5700 rigs dropped a total of 2.x mhs for no reason about 1-2 weeks ago.  So about the same drop of 0.5mhs per card.  I was running phx 4.9.   switched to 5.3 and it didn't change.  Only explanation is indeed DAG size. 

[bobben2]

Use the latest Poloniex miner
Driver 19.3
-No Bios mod
-rxboost 50
-mt 1
Write in private if I can help.

Don't download anything from random people on the internet.

So I upgraded to PhoenixMiner 5.3b and AMD driver version 19.7.5.  Those changes did not change anything!
Then I added command line options  -rxboost 50 -mt 1  and voila - all cards except 1 are above 30MH/s again :-)
Some further tuning is required and I will monitor the amount of memory errors in HWinfo64.
Since the rig is in a remote location and I log in using Chrome remote desktop I dont want to do any BIOS mods before I get to go on site.
Thanks for the tip to use rxboost, mate!