• Welcome to Overclockers Forums! Join us to reply in threads, receive reduced ads, and to customize your site experience!

New build power problems :(

Overclockers is supported by our readers. When you click a link to make a purchase, we may earn a commission. Learn More.

jmprince80

New Member
Joined
Dec 23, 2013
A few weeks ago I started to look into the viability of alternative ways of making some extra money online. A promising method turned out to be by mining <a href="http://a.com">Litecoins</a> so I set about buying the required hardware.

Litecoin mining needs sophisticated GPU(s) in order to maximise the yield, so I initially tried to get a less expensive model of the ATI R9 280X by XFX. This was to set me back around £250, but was oversold by the supplier, so I waited a week for an email from the supplier saying they were unable to fulfil my order. Consequently, I ordered a more expensive (but better) R9 280X manufactured by Gigabyte from another supplier which cost just shy of £280.

I needed a decent motherboard and CPU to go with this, since prior to this I only had my HP Probook, so I ordered an ASUS Z87-K motherboard with an Intel i5 Haswell Quad Core CPU, costing £250. I also bought a cheap case and PSU from ebay for £50, and 8Gb of Kingston Hyper-X DDR3-1600 RAM, also at £50.

So, total cost of the system comes to £630 so far, it won't always be used for mining Litecoin, and I don't expect to fully recover the cost of the parts by mining alone, it will be a good machine for my Games Developer course which I am almost a year into, and also as a general multimedia PC, or gaming box (the R9 280X is pretty well specced, toting 3GB of ram and a GPU clock running at 1100MHz, RAM clocked at 6000MHz) I didn't really want to pay more than £500 but decided to pay a bit more in the end as I know eventually I will earn some or all of the money I spent on the machine back.

First things to arrive were the Motherboard + CPU, RAM and the Case/PSU. I set about putting everything together, its not really rocket science building a PC, I used the old hard drive from my old (sadly dead now, though it served me well for 5+ years) HP TC4400 Laptop/Tablet convertible, installed Linux and Windows 7 dual boot, thought I would give 7 a try as the graphics drivers are more recent than the Linux versions, but to be honest I very much doubt Windows 7 will get much usage outside the occasional Reason 5 session or for playing games which only run on Windows. Oh, and probably for some Unity3D development later on.. The whole process of installing windows, and the 20+ drivers and support programs (weighing in at over 30gb for a 'fresh' install) only served to remind me how very lame Windows is. I still prefer XP, to be honest but even that is used begrudgingly and only when it is absolutely necessary.

I got the GPU a couple of days later, and found that it wouldn't fit inside the case properly (the 3.5 drive bays at the bottom of the case got in the way of the huge cooler) so I had to bend them out a little to accommodate, other than this though, everything else seemed fine.

So, apparently, a 750 watt PSU should be enough to power my board and the R9 280X, according to what I have read online, however this is where the trouble begins :/

Whilst I was waiting for the GPU to arrive, I started mining LTC using just the CPU, averaging 75,000 Litecoin hashes per second (75 Kh/s) which is around 4 times faster than the CPU in my i5 based laptop is able to manage. Note that this was only when using the 64 bit version of Ubuntu 13.10, when I used a 32 bit kernel the speed was actually slower than on my laptop. No problems with the power supply at this point at all.

Then the GPU arrived, and I installed the drivers on Windows 7 (64 bit) and Linux (also 64 bit) found that performance in mining was far worse under Windows than it was under Linux, so immediately ditched windows for this task.

Took a while to get stable mining working under linux, but when I did, I decided it was time to put the case back together and leave the machine under my desk to do it's job and start paying for itself. Here is where I began to experience problems.

Mining with the GPU only was working seemingly OK, and hitting around 750 Kh/s, so I thought I may as well enable CPU mining to run alongside it, as soon as I did, the system immediately hung and reset.

OK, no mining with CPU+GPU simultaneously then, but this really shouldn't have been a problem with a 750 watt power supply, anyways, I put the case back together and was running it headless for a few hours, mining fine, then I decided to log in via SSH to check out the status of CGMiner, as soon as I did this, the machine immediately hung and rebooted like before, which was quite frustrating, and I began to suspect power supply problems - the GPU must have been drawing very close to the maximum output of the PSU, and waking up the CPU to run a process to log me in seemingly tipped it over the edge.

I had a look through the manual and BIOS of the Z87-K motherboard and found that the motherboard had an Anti-surge feature, which I assumed was what was responsible for the cut outs, so I disabled it, since surely my brand new 750 watt power supply should have had no problems running my system....

Restarted it, loaded up CGMiner and all seemed well, I'll stop tinkering for now and head out to see the GF, leave the machine to do its thing and make me some $... about 20 minutes later the PSU went BANG! twice, and the machine wouldn't switch back on. I immediately disconnected everything to prevent chance of any further damage and then tested the PSU, all outputs were dead except the +5VSB (standby) line. Great, I thought, now I'm going to have to return the PSU.

Being quite impatient, and knowing that if I sent the blown up PSU back to the seller now, I am unlikely to receive a replacement or refund until well into the new year (and the fact that the seller is probably going to be pissed at having to replace another part for me - the clips on the front of the case they sent me were all broken when it arrived in the post) I decided to buy another 750W PSU from a local computer shop, costing me a further £50, it worked until I started mining, then I could smell overheating, so I switched the machine off, and it wouldn't power back up.

Returned it to the shop 2 hours later as a DOA, and they replaced it for me, second power supply done exactly the same thing, not sure where to go from here really, I looked up the original 750 watt PSU and found it selling for £18, so its obviously a POS, but the fact that the 2 I got from the shop also stopped working seem to suggest to me that either A: the shop have a bad batch of 750W PSU's (which I'm going to try, offering them to test my system if they want to) or B: for some reason, the GPU is drawing too much current and killing the PSU's.

The second PSU has 2 12v rails rated at 22A, I assume one is shared between the 6-pin PCI-E and the 4-pin CPU connector, with the remaining being the supply for the 4 pin molex connectors and the SATA power (the 8 pin PCI-E power on the GPU is connected to two of the molexes via the supplied adaptor)

Also, regardless of the Anti-Surge settings in the BIOS, surely a decent PSU should shut down if something is drawing too much current, not just burn out!?

Power consumption Radeon R9-280X

System in IDLE = 121W
System Wattage with GPU in FULL Stress = 365W
Difference (GPU load) = 244W
Add average IDLE wattage ~10W
Subjective obtained GPU power consumption = ~ 254 Watts

Last time I started up CGMiner, it wasn't even under full load - I changed Intensity to 12 from 13, and utilization was at around 70%, yet still the PSU dies.

Assuming my power draw was 300W max (should have tested with multimeter really) this is still only 25A and is split between two rails which can supply 22A each, so im at a loss as to explain what is going on here. CPU was not under load, but even under full stress shouldn't use more than 100W / 8.33A, so again should be within spec of the PSU.

Any comments / help would be much appreciated!
 
Cheap eBay power supply. Plus another power supply without a brand name provided. You're buying the cheapest gear you can find, it seems, and then complaining about what a "decent" PSU should be able to handle.

Was the shop PSU new or used? I assume new. Any branding on it?

IMHO, be thankful it didn't fry any of your other hardware and pick up a quality PSU. Seasonic, for instance. Don't just buy whatever's on the rack at the local store, look into what they're selling.
 
Hmm, well the second PSU is branded "ace". Both PSU's were new, the first was included with the case I bought, the second was brand new in the box. I'm thinking of just taking it back tomorrow and asking what else they have, I'd rather pay more for something that isn't going to break within hours due to my "abnormal" use of my system, rather than keep spending more £50's and having to fight sellers for refunds.
 
Bit the bullet and ordered an XFX Pro 850w modular.. hopefully that will sort out my power issues, by the looks of it I should be able to chuck in a second card when funds allow. Cost me just shy of £100 though.

Still, I should be able to mine 2+ LTC/week and then trade it to make more so this £100 should pay for itself within a week anyways.

Now the fun part will be getting refunds on the crap that I bought, grrrr... probably end up with a store voucher or something from the shop, guess I can use it to buy the wife a present or something :)
 
I noticed when I was mining on the crap PSU's, I got a lot of hardware errors with my graphics card (Gigabyte R9 280X which is factory overclocked to 1100 / 1500) at a high intensity (13 or above) but no errors at intensity of 12, but then Kh/s dropped dramatically.

I even tried intensity of 13 with core underclocked to 900 and ram to 1250 but still loads of errors, I assume this would be due to power supply instability?

With a decent PSU I should be able to push this card to 800 Kh/s+ and use the CPU for mining too (~75 Kh/s)

Using electricity at the office which is very cheap :)
 
Back