Thanks Lone!  Amazingly, it seems like just opening up Wattman has resolved this issue.  When I opened the AMD utility, I went to the Wattman tab for my first GPU.  The Voltage control was set to Auto so I toggled it to Manual.  But either right before or right around the time i did this (before clicking Apply, mind you), the speed started to increase on all 4 GPUs... pretty much to their expected rate.  I went ahead and applied the change to manual on all 4 cards and they are now running at the expected pre-overclocking speed.

Out of curiosity, is there any downside to leaving the Voltage control toggled to Manual?

Thanks again for the tip!

Happy weekend everyone!  I have a weird issue that is occurring on my 2nd mining rig and was wondering if anyone had experienced similar and/or had any suggestions on what to tweak to try and fix it.  Here's the scenario...

Rig Details:
- i4790k CPU
- ASRock H81 Pro BTC R2 Mobo
- 16GB RAM (2x8)
- Win7 Pro
- 16 GB Virtual Memory
- 1200W Plat PSU
- Claymore ZEC Miner v8

I had 2 MSI 470's running for 3-4 days very stably.  With no tweaks at all, were running about 160 S/s.  After undervolting and setting core/mem clocks to 1300/1900, they were producing about 170-175 S/s.  I had an issue with strapping the first GPU, so reverting back to original BIOS.

After the molex cables from Phil arrived yesterday, I hooked up the 3rd GPU, a Sapphire 470 8GB.  This also ran fine, providing about 180 S/s with no mods (but it comes factory over-clocked).  In addition, the 2 MSI 470's were still running at previous speeds.

The problem started after I hooked up the 4th GPU, another MSI 470.  While my system recognized it fine, after running Claymore for a while, I realized that the hash-rate on all 4 GPUs had dropped.  Now, the 3 MSI's are barely getting 150 and the Sapphire about 155... so, all are about 25 S/s short.  Even stranger, when I set the core/clock speeds of the MSIs to 1300/1900 in afterburner, it has no apparent effect on speeds.

I am using the exact same config file with Claymore v8 as I am on my first rig and all other settings seem to also be inline, but all 4 cards on rig #2 are running about 25 S/s slower than they should be since I added the 4th GPU.  I double checked virtual memory and it is set to 16GB just like rig #1, so not sure what else to check.

Not sure this matters, but I have the 4 GPU's plugged into slots 1, 3, 4, & 5 (all x1 slots).  Slot #2 in the x16 slot and although Phil sent me a ribbon riser, I still need to figure out how to connect it given the design of my rig.  So, after running with USB powered risers in slots 1 & 3 stably, I added the Sapphire to slot 4 and then the 3rd MSI to slot 5.

Anybody seen anything like this before on this or similar Mobo?  I know there are tons of people running this Mobos at full speeds with 6 GPUs, so I must be missing something.  Any suggestions would be highly welcomed.

yes I was pleasantly surprised to see that it is out for delivery today as the original ETA was tomorrow!  That means I should be able to get my 2nd rig running with 5 GPUs by tonight.  Thanks again!

So, can i ask which pool most of you here are using for ZEC?  I have been on flypool since the start and the payouts are very quick and reliable. However, I am beginning to wonder about what seems like a pretty big hash-rate difference as reported on their dashboard vs what I see directly in Claymore.  My 2 rigs are currently showing 1,050 S/s consistently but my avg hash-rate at flypool is around 960. Not only that, but the range of reported rates is still all over the place on flypool. In the last 5 hours alone, it showed a high of 1130 and a low of 770... all this time both rigs were at full capacity.  I don't have a huge problem with the spikes as long as the average H/R is being recognized correctly, but it seems to be about 10% short.

Is this normal?  Wondering if I should try Dwarfpool or Suprnova as both seem to be getting some love in other threads I've read.

ummm... dare I say that this seems like a huge waste of headroom?  Yes, I understand that it is ideal to have a max load of about 25% less than your PSU's wattage rating, but you indicate that your system has 70% headroom.  Not sure how you can ever ROI a system that includes excessive costs from idle PSU wattage capabilities, but you're right lol... you are certainly prepared to max out those 480's  

yup, i have read way to many posts about the problems with C9 so will be holding off on updating for now.  I suspect Claymore will be able to fix or at least mitigate the power spike issues that seem to be causing most of the problems. Doesn't seem worth that hassle and probable down-time for my small operation, so will see what happens in the next few days.

Awesome Phil! I really appreciate that!!  I have a few ribbon risers around but none are of the x16 variety, so that will be a perfect "surprise" 

Hey Aries... yeah, that is the exact one i am using for my 2nd rig (6-GPU hopefully).  I have the 1000W version powering my first 4-card rig and really liked it, except for the fact that both are short of molex power cables (if you are using powered risers, that is).  I think it's not a problem for you because I believe I remember that your builds used the ribbon type risers.  Lucky for me that Phil has a couple extra that I just bought from him, so I should be up to 5 GPUs on this rig after they arrive.

Happy to report that I got my 2nd rig up and running last night!  Currently running 2 MSI 470s mining ZEC at about 165 S/s each straight out of the box.

The only issue I had so far is that I initially tried to plug the 2nd GPU into PCIe slot #2 (the x16 slot on the ASRock BTC Pro Mobo).  For some reason, this didn't work. Couldn't even make it to post.  When i tried the exact same in slot #3 (x1), it worked fine.  

So, my question is this:  do i need 1) a different riser for this slot? or 2) do i need to do something in the bios to make this work with the powered x1 USB riser?

Nope... as of now (over 2 weeks after 1.03 was released), their stinking Z-wallets STILL do no work (at least on FlyPool).  This just baffles me. How can the devs release this without Z-wallets working alone is shameful, but the fact that they have not fixed it still... what, 5-6 weeks after release... is a down-right travesty!  Is it any wonder that the price of ZEC continues to drop?  Why should anyone have any confidence in this crypto at all since the pathetic devs can't even get their Z-wallets working? Really, really sad and truly pathetic!

Good to know thanks. I will highly consider them for my next build.  I just hate getting everything ready to go and then being short on power cables.  Granted, I could have checked it any time in the last 3 weeks but was just too lazy. But still, you would think that these higher end PSUs would have more than enough cables, so I will check out EVGA next time.

Thanks Phil. PM sent.  Once again, you are the best

So, I am most of the way through my 2nd mining rig build but when I popped open my power supply to hook up the cables, I realized that I will yet again be short on the molex cables    This happened on my first build since my x99 mobo required a molex for added PCIe power, putting me one 2-molex connector cable short. Luckily, Phil came to the rescue as he had an extra one from the same 1000W Rosewill Quark series Plat PSU.

This time around, I went with the Quark 1200W since I want to power 6 GPUs off an ASRock H81 Pro BTC Mobo.  I also thought i read that this PSU had more molex connectors but alas, it only has 4 on 2 cables     Assuming this Mobo will also require extra molex power for more than 2 GPUs, this means I will only be able to hook up 2 of the 5 GPUs I currently have until I am able to secure 2 more 2-molex cables.  The bad thing is, it seems that since this is a full modular PSU, only cables from this brand and series will work with this PSU, and I cannot find them available anywhere online, including at the Rosewill store.

So, I would like to ask if anyone might have 1 or 2 extra of these laying around they would be willing to part with. I will of course be happy to pay a fair price in BTC.  Also, if anyone knows where these might be available online, I would appreciate the tip.  Thanks!

http://www.newegg.com/Product/Product.aspx?Item=N82E16817182354

I am in the midst of building my 2nd rig, which I'm hoping to get 6 470's running on an ASRock H81 Pro BTC 2.0 Mobo.  My plan is to keep all 6 GPU's off-board using powered risers. I am building this onto a DIYPC open test bench like my first rig but rather than mounting the GPUs onto wood planks, I am hoping to somehow attach them to a wire rack shelf I have bought. Not 100% sure this will work though but am hopeful as my first rig is not really mobile (ok since it will stay in my garage year round) but I want this 2nd rig to be mobile so I can move it around my house depending on time of year. So, I will try to build into this smallish wire rack shelf but if it doesnt work, I am looking into other options.  I found something that looks really nice on ebay so would like to get some opinions on it.

http://www.ebay.com/itm/232139141160?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

The frame itself is exactly what I am looking for but cannot seem to find it without all the extra stuff this comes with.  This is pricey but it does come with a Plat PSU 1200W and 6 risers + all cables needed.  Given this, it seems like a decent deal, but my real question is about that PSU.  I have never seen one like this before so wondering if there are any draw-backs vs the standard ATX style PSU. It looks like it may only have PCIe connectors though, meaning i would might still have to buy a small ATX PSU to power the remaining components. If so, this would be a bit of a waste since I will be using 6 undervolted 470's that should easily allow the full system to be powered by 1200W PSU.  Any feedback on this item would be appreciated.

Yup, I will 2nd that.  Great card like Phil said and is also very easy to mod the bios using strap-1500 method. Oh, and they look pretty dang sweet too. My first rig was built with 4 of these and runs quiet, cool and smoothly.  I have 3 more with 1 more arriving tomorrow to build my 2nd rig.  Really hard to beat, especially at that $168 price point.

Very Nice!  Exactly what I was looking for for my next build!  Did you buy that frame somewhere or build it yourself?

Wow! I almost pulled the trigger on that but when i looked into the rebate details, I don't think the full $40 is valid...only the current $25 Dec rebate.  They have the $15 rebate over-lapping with it from Dec 1-4, but I seriously doubt we would be able to claim both rebates off 1 purchase. Mainly because they require that you send in the UPC symbol cut from the box, and you can of course only do that once.  Seems like adding the $25+$15 is a mistake on this site.

Yup... totally agree! And, these are very easy to mod the bios as well, so win-win-win in my book.  I only wish that MSI didn't limit their rebates to 1 per GPU model. Otherwise, I would probably pick up 4-6 more at this price.

On the 480 vs 470 issue... most of what I have seen indicates that hash-rates of the 480s are only marginally better than the 470s.  But, they also cost more and draw quite a bit more power, which would seem to indicate that 470s are usually going to be the better choice for overall mining efficiency.  However, I have seen some people claiming that they can under-volt their 480's to nearly mirror the power consumption of a 470, but frankly, that doesn't really seem possible given their respective power specs.

FYI (since I know there are a few on this thread that like this GPU)... Amazon has the MSI RX 470 Gaming 4GB for a net price of only $167.99 now. $192.99 up-front cost but MSI has now upped the rebate to $25 (was $15 the past few months). I just purchased 1 so now I am up to 5 (of 6) GPUs to build my new rig.

https://smile.amazon.com/gp/product/B01JS9F9K4/ref=oh_aui_detailpage_o00_s00?ie=UTF8&th=1

Back to ZEC for a moment... can someone explain the reward increase thing to me?  I thought I had read early on that the first month or so of ZEC mining would be "slow" and then at a certain point (block 20,000 i thought), it would be 3 or 4x what it is now.  But alas, now what little info on this I can find, I can't seem to comprehend how it will impact those of us who are mining ZEC.