zec mining stresses rigs differently than eth

[nerdralph]

When Sia mining was briefly the most profitable altcoin, I noticed that overclocked cards that were stable mining eth for days sometimes crashed mining Sia.  I've found similar issues mining zcash.  Not only do the clock settings have to be re-tuned for zcash, but I've even found ribbon risers (aka blue tape risers) that didn't give me trouble mining eth were causing cards to crash mining zcash.  zcash mining (at least with the silentarmy kernel) transfers much more data over the PCI-e bus than eth does, and almost all ribbon risers fall well short of complying with PCI-e bus signal integrity design requirements.
Even in the heydays of eth mining, there were a few people I saw posting about risers saying they would not touch the ribbon risers.

[Newwsr]

I am using this

https://pt.aliexpress.com/item/Adapter-Cable-USB-3-0-PCI-E-Express-Extender-Riser-Card-Adapter-to-SATA-7-15/32692508532.html?spm=2114.02020208.3.1.zIyaP2&ws_ab_test=searchweb0_0,searchweb201602_2_10091_10090_10088_10089,searchweb201603_1&btsid=811a355c-258b-4bba-9f4e-9ca64f44e82b


Minera eth + sia without any problem for very stable days.
Now in zcash crashes every time is 0.0sols

[bathrobehero]

All hashing algorithms have different characteristics so they stress different parts of the card.

It's not a riser issue though I'd highly recommend only using powered USB risers.

Also, just very generally speaking, the less optimized a miner is, the more you can overclock because the card is not stressed as much as if you'd have a very optimized miner.

[antantti]

zcash mining (at least with the silentarmy kernel) transfers much more data over the PCI-e bus than eth does, and almost all ribbon risers fall well short of complying with PCI-e bus signal integrity design requirements.

I can confirm this. One gtx970 at PCIe x16 slot alone without riser can consume up to 28% of that slots bandwith (8GT?) when mining zec.

If I had to guess, this is the reason for this whole windows/ linux/ amd/ nvidia/ sse2/ avx/ avx2/ i5/ i7/ sols lottery.

[ryantc]

I thought my riser had bad connections. I can use a 16x-1x and with ETH I can add another 1x-1x to make the extension long enough so I can put cards well apart, but with ZEC, miner complains about the and gives 0S/s 

[antantti]

I thought my riser had bad connections. I can use a 16x-1x and with ETH I can add another 1x-1x to make the extension long enough so I can put cards well apart, but with ZEC, miner complains about the and gives 0S/s  

I had one case where card with riser did 33% less that identical card sitting in a slot without riser. You can see more of these reports in zec forums.

It is easy to test, try only one gpu without riser @x16 slot. Remove/ disable everything that could split/ use pcie lanes.

Are we chipset/ cpu pcie lane limited here?

[molitar]

When Sia mining was briefly the most profitable altcoin, I noticed that overclocked cards that were stable mining eth for days sometimes crashed mining Sia.  I've found similar issues mining zcash.  Not only do the clock settings have to be re-tuned for zcash, but I've even found ribbon risers (aka blue tape risers) that didn't give me trouble mining eth were causing cards to crash mining zcash.  zcash mining (at least with the silentarmy kernel) transfers much more data over the PCI-e bus than eth does, and almost all ribbon risers fall well short of complying with PCI-e bus signal integrity design requirements.
Even in the heydays of eth mining, there were a few people I saw posting about risers saying they would not touch the ribbon risers.

Not having issue with my one GPU that is on a powered riser.  Using PCIe to USB 3.0 powered riser.

[xxcsu]

i was mining zcash in the past few days with genoil's miners . i have no problem at all till version 0.5 any of my 29 rx480 cards i used for zcash mining with custom bios . tried today genoil 0.6 miner , all my rig crashed some after 5 minutes some after 2 hours . for me doesn't matter if using powered risers or not, i got a same hashing speed / cards  with risers , or card sitting in the pcie slot .
Two thing i noticed
- mining zcash is using around 40% less power at the wall  , than mining ETH with the same 6 card rig setup
- some of my rx480 cards hashing power is the same with factory bios and my own eth mining tuned bios - yes flashed back some cards to try

[ryantc]

I thought my riser had bad connections. I can use a 16x-1x and with ETH I can add another 1x-1x to make the extension long enough so I can put cards well apart, but with ZEC, miner complains about the and gives 0S/s  

I had one case where card with riser did 33% less that identical card sitting in a slot without riser. You can see more of these reports in zec forums.

It is easy to test, try only one gpu without riser @x16 slot. Remove/ disable everything that could split/ use pcie lanes.

Are we chipset/ cpu pcie lane limited here?

not really sure, my desktop runs 2 cards (one in 16x slot and one on riser) fx8320 on a 970 mobo
another rig runs 4 card (all one riser,  3  usb riser and 1 16x-1x riser) sempron 145 also on a 970 mobo