CORSAIR - CX Series Modular CX750M 750W ATX Power Supply

[thowell76]

This power supply is $69.99.   Is it a good PSU to start out with and it would be powering a RX570 and planning on at least two more cards once I get my tax money and when I can find them.   It looks like I can safely power 4 GPUs but would it be able to handle a 6 card rig, if I make it that far? 
 
I am currently running my GPU off a no name PSU that is 400watt and I am using two molex connectors to the PCIE power converter to power the GPU.   Seems to be ok but if I mess with any of the GPUs settings I get terrible performance.   I have chalked this up to probably the PSU not doing its job correctly.   

https://www.bestbuy.com/site/corsair-cx-series-modular-cx750m-750w-atx-power-supply-black/8324202.p?skuId=8324202

I have a guy that wants $60 for a EVGA 750 watt USED bronze+ PSU and I thought that might be a good deal but probably not.

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[leowonderful]

PSU deals have been pretty scarce recently, but this Seasonic 550W unit is available for just around $40 and is Gold rated which should save you a bit of money in the long run with mining. It's got just two PCIe 6-pin connectors, though. Note there is a rebate attached to this PSU but everything I've seen about it shows it's a good unit.

Link to deal: https://www.reddit.com/r/buildapcsales/comments/82eqfk/psu_seasonic_focus_series_ssr550fm_550w_80_gold/

IIRC the green CX PSUs were not good with internals and the ones with just black or grey coloring were the better ones. I'm not completely sure, so if I'm wrong, feel free to correct me.

[whitrzac]

There's not a chance in hell you would get 6 cards to run reliably on a cx750. They have issues when pushed hard.

4 rx580s/570s is about all you want to do on a cx750. PSUs are more efficient at ~50-80% than at full load.

[thowell76]

There's not a chance in hell you would get 6 cards to run reliably on a cx750. They have issues when pushed hard.

4 rx580s/570s is about all you want to do on a cx750. PSUs are more efficient at ~50-80% than at full load.

I thought 6 would be pushing it.  So when someone says a 1200watt is over kill for a 6 card rig 1070 and rx480, would you agree?  I do have a question about hashrates and maybe if it is related to what I am seeing on nanopool’s stat site.  Do you have spikes in you hashrate or should it be relatively flat line?

[thowell76]

 I am mining zcash with rx570 and should do 270 sol/s our of the box but I am averaging 250 sol so I am wondering if I am not giving it enough power to cause this

Can I attach a picture from my phone?

[manji]

RX570 has TDP 120W x 6 = 720 Watt. only has a power rest is 30W better using 1000W for 6 cards, for keep another part doesn't to lack power.

[tadeus1]

Even 4 x 570 is at the limit of this corsair cx750.
I would not risk it with more than 3x 570 and that's single mining only.
Dual mining 570 can reach 150 watts

[thowell76]

Even 4 x 570 is at the limit of this corsair cx750.
I would not risk it with more than 3x 570 and that's single mining only.
Dual mining 570 can reach 150 watts

I was thinking 3 would be good for this and I don’t know when I could add the 4 with finding a good price

So should my hashrate go up to 400 sol and drop to 60 sol within an hours time or should it stay consistent with say 270 sol

[tadeus1]

3 should be ok.

By the way, Rx570 is not very efficient for equihash algorithm.
Try ethereum or crypto night. Also bios mod.

[FalconZA]

Just keep in mind it is a Bronze rated PSU, so there will be a slight increase in electricity costs compared to a Gold rated PSU.

[thowell76]

3 should be ok.

By the way, Rx570 is not very efficient for equihash algorithm.
Try ethereum or crypto night. Also bios mod.

Since I am using an 8-10 year old power supply I was afraid messing with the bios and doing something bad to the card if I wasn’t giving the card enough power.   I did the bios update once but rolled it back when I realized I was on a old driver version so I updated it to the latest.  I will try it again tonight unless I should go to a particular driver.  When I did mod the bios and played around with setting in afterburner, I started to see some real low hashrates from 250 to 150 so I revert it all back.

I was going to start mining ETH but didn’t spend the time to install the wallet and get my address so I went on with Zcash because I had that address already. 

[adaseb]

These are great PSUs.
Used them since 2013

However you can't do more than 4 GPU with them due to the fact that there are only 4 connectors.

Make sure to undervolt properly so you don't go over the 750watt limit.

[thowell76]

Just keep in mind it is a Bronze rated PSU, so there will be a slight increase in electricity costs compared to a Gold rated PSU.

I am taking that into account but I was going to worry about it when I am running more GPUs.   I am getting about 14 cents for electric per killowatt.  Is that about average?   

I am trying to determine if I should upgrade my motherboard before I do anything else.   I think I might start a new thread so that it doesn't bleed together with this one.   

[pickleburglar]

RX570 has TDP 120W x 6 = 720 Watt. only has a power rest is 30W better using 1000W for 6 cards, for keep another part doesn't to lack power.

TDP is what you can expect on the average but there is no way you'll run a rx 570 when limited to just 120W per card. You can expect the cards power usage to fluctuate +-50% easily in short <1s bursts and as soon as all the cards hit their peak power draw at the same time your system will crash.

From my experience, a modded 570 with adjusted voltages and mem straps will need ~165W available per card to mine eth at full speed and stability. 750W will run 4.

Also the gold/platinum/whatever PSU's are really pointless given that the investment would have a ROI of over 5 years to match a lesser rated PSU. That's worse than buying solar panels or a small wind turbine to power your rigs in terms of profit.