PSU issues with RAID arrays, OC's, or high usage

[Panagiotis Raris]

Just figured i would post to suggest checking ones PSU setup in the event of random BSOD's or warnings. I had been trying to figure out a dozen or so seemingly unrelated problems for literally months.

I bought a 700W PSU initially, and up to a certain limit, it works just fine. I never built a system with so many add-ons; i should have gone with a 1200W PSU. A new, 1200w PSU costs around $180-$220; two of these cost $100; with the connector is $120-$130. The caveat is its 2 separate PSU's. Thankfully, i have the space in my HAF 932.

First, check connectors. especially cheap 4 pin MOLEX to SATA power connectors. these caused me a total disaster with my RAID array. I ended up soldering some connections together (male/female MOLEX connectors that wiggled/slid out) on my PSU's. I still havent rehashed the data, just did raw disk image dumps onto a 3TB external to figure out later.

Second, disconnect unneeded items, then systematically test each item on its respective power cord. this eliminates individual cables.

Third, doublecheck your OC stability. This rules out system related issues.

*OPTIONAL - If you have or have access to an oscilliscope, use it. my 3.3V was always around 3.1V; 12V and 5V under as well. My replacement PSU had the same stats. When we checked with an oscilliscope and a proper volt meter, my voltage was fine, but fluctuated madly when the RAID array came under heavy use, ie render times.

Eventually, i bought a second identical PSU, an Add2PSU adapter so both PSU's would run together, and split power loads as evenly as possible across both PSUs. As you can see from below, its a fairly power hungry system. It resides in a fairly hot office, hence the emphasis on cooling. I bought a second PSU and PSU splitter as it was $60 total, versus $200 for a new PSU.

I have had ZERO problems since i installed a second PSU.

System specs
Rampage III Gene Motherboard
Core i7 950 at 4.2Ghz 21x200
Corsair H50 with push/pull fan configuration
24GB Kingston HyperX RAM at 1600Mhz
Galaxy Razor GTX460 1GB Single Slot
OCZ Vertex 2 120GB SSD
ARECA ARC-1222 8x RAID controller
- 8x Samsung HM500JJ 500GB 2.5" HDD's
- 4 each in AMS RAID Backplane cages (2 total)
1TB Seagate HDD
2 Apevia Aqua 700W PSU's
- Connected with Add2PSU dual-psu power connector
Pioneer MBK-206 Blu Ray burner
Scythe Kaze 4x fan controller
Scythe USB memory card reader
1x 230mm fans
1x 140mm fan
4x 120mm fans
1x 80mm fan

Here is how i split the power consumption (evenly as possible)
PSU 1 - Apevia Aqua 700w
Motherboard
CPU
Vertex 2 SSD
Corsair H50 CPU cooler water pump
2x 120MM fans for the push/pull H50


PSU 2 - Apevia Aqua 700w
GPU GTX460
All remaining fans
8x Samsung HDD's via 2 4-pin MOLEX connectors
1x Seagate HDD
Blu Ray burner
Memory card reader
Fan controller

[Zoran Vincic]

You shouldn't need a 1200w psu for that system

here's my system's specs

i950 @ 4ghz (20x200)
Corsair H70 (older one)
Gigabyte x58a-ud7
24gb corsair vengeance (stock speed)
both GTS450 AND GTX 570 cards (3 monitors + TV)
Samsung 830 SSD
I won't list the specs as there's a mix inside but I currently have 12 7200rpm drives inside (no dedicated RAID card or RAID at all currently)
LG BDRW
Pioneer DVDrw
2 200mm case fans
2 120mm fans on corsair h70
4 120mm fans on GPU's

I won't list all of the peripherals.


And now the interesting part, my system is powered by ONE Seasonic 760w X series PSU and connected to a APC br1800 UPS which shows how much power the system draws.
Here's the approximate figures (together with one 24'' CCFL monitor that's on battery too).
Idle - 240 - 260W
PPRO cs6 running idle around 300W
Working in PPRO 350-400W

I won't list consumption when rendering as it jumps around all the time but I did a test where I maxed both cpu and gtx570 with synthetic tests ("killed" the gpu with Furmark), consumption is between 550 and 600W and never goes over 600W.

CPU and GPU are enormous power hogs, and given the fact that your system has only one GPU and it's less speced than GTX570 in my system, I highly doubt that your system in its' HIGHEST load draws more than mine. Although I don't have a RAID in my system, if you do the math you can average the consumption. The average 7200 rpm drive draws around 1W when idle and 3-4W when reading/writing. I doubt that the Areca controller draws more than 10W.

But I can give you a small pointer as we have the same CPU, mine was able to reach 4.2 GHz (21x200 as yours) only with a REALLY BIG jump in Vcore and it was not stable even then. On 4GHz Vcore is 1.31V and it's rock stable.


The PSU manufacturers will tell you that you really need that 1200w PSU, but luckily the real world figures are somewhat different.

[Harm Millaard]

Zoran,

It is a myth that a 1200W PSU consumes more energy than a 650W PSU. Often it consumes even less energy, so from an electricity bill point of view, the 1200W may be more attractive. Why you may ask?

Well, the power drawn from the wall outlet is what your computer really consumes, plus the efficiency loss in the PSU itself.

We all know that a PSU gives the best efficiency when the load is around 40 - 70% of its rated capacity and we also know that the fan in the PSU can run at lower speeds than when the load is much higher, so it runs quieter than a smaller PSU.

FYI, most HDD's consume around 7.5 - 8 W during disk access and spin-up and if you don't have a dedicated raid controller to enable staggered spin-up, with 12 disks you will have a load of around 100W at boot time from the disks alone.

I suggest you go to eXtreme Power Supply Calculator and get the pro version. It is cheap and gives you lifetime access.

Now enter all your components, including additional items you foresee in the future. Set system load to 100% and capacitor aging to 30% and calculate the required wattage of the PSU, paying special attention to the amperage on each rail. That is where several PSU's give problems. They claim the correct wattage, but fail on one of the rails in amperage. For safety, add around 10% to the calculated wattage.

In your case, adding 4 USB devices, no PCIe cards, no FW devices, no fan controller or multi-card reader, the suggested PSU should be 1076W and 9.9A on the 3.3V rail, 33.6A on the 5V rail and 72.9A on the 12V rail. so you are taking serious risks with that low capacity PSU and increasing the electricity bill by using such a PSU.

[Zoran Vincic]

Harm, that's exactly what I'm talking about. You too sound like you've been brainwashed by the PSU manufacturers.

I have given you a real world MEASURED numbers and yet you tell me that I need a 1kW psu for a machine that never draws more than 600W (and that's with a 24'' LCD which draws around 20-30W itself).

You need quality not quantity, that seasonic 760 PSU costs more than some 1kW PSU's.

And one more thing bugs me, you say that the PSU is most efficient between 40-70% load.
Take look at these figures for this Seasonic unit I'm talking about:
Measurements: Seasonic X-760 : 80 PLUS Gold: Four Efficient 700-850 W Power Supplies


Then you say about the power draw from the wall, I have given you figures that a quality ups device delivers to the machine, there really should be no dilema about them, that's how much power it would draw from the wall.

About the HDD's, you're not right, most 7200rpm hdd's do not draw more than 4W when fully utilized (actually most of them hover around 3W, but some HDD's do draw more power, WD Black for example) They do draw more power on startup, but that's why good MBO's and controllers have a disk startup delay option.

One thing left to consider is noise. And here's how it goes with this seasonic unit I'm using, when my computer idle's the PSU fan doesn't run at all. At full load I can't hear it as it is drowned by the GPU and CPU fans.
Again, that's a QUALITY PSU right there.

[Harm Millaard]

Thanks for the link to Tom's, since it confirms my statement, the best efficiency is between 40 - 70% and in this case around 50% in the measurements Tom did.

This test also confirms that your 12V rail is not enough for the 12 disks you run plus the other components.

Look here for idle power consumption: Enterprise Capacity 3.5 HDD Cloud Storage 4TB Hard Drive | Seagate

Varies idle between 4+ to almost 8 W and average operating power varies between 4.5 and 12W with an average over all models around almost 10W.

[Zoran Vincic]

I give up...

[Harm Millaard]

Yeah, it is hard to refute manufacturers power consumption claims, that are usually rather optimistic.

[Panagiotis Raris]

i can confirm 700w is NOT enough to power my system, even with it stripped down ie removing power to 5 fans, memory card reader, blu ray drive, internal SATA drive, fan controller, and minimal other devices plugged in.

i received a new PSU from Apevia and my 3.3v did not fluctuate as badly (almost a year old), and since installing the second PSU i have had zero issues.

i began to suspect the PSU was the culprit, and even once used a second PC PSU to power the RAID array by itself to finish a job. that is when i got a replacement PSU. i bought a second one and wired them together now (adapter that triggers 2nd PSU to come on independently). i also have each PSU's power cable plugged into different sockets on different 120v lines so i am not overdrawing from one outlet.

When this system is in full use ie after effects etc, it would commonly BSOD when at 100% utilization CPU/HDD's/RAID array, so until i got the second PSU in, i underclocked to 3.4Ghz and ditched unneeded devices. I also received $25 off the new PSU through Apevia, so a second PSU cost me only $25.


Old thread with more details. the replacement PSU worked fine but calculating required voltages i need closer to 1100w PSU, and since my case can take it, and it was only $25, i went for a second PSU.

Obviously next builds i will calculate power and overcompensate to begin with. I just felt it may be a good idea to give your power consumption/requirements a looking over if you are having stability issues. It always passed prime95 and intel burn test; just had issues when all the HDD's, graphics card, RAID controller, and fans were at full blast using full CPU and RAM. Also i plan to add 3x3TB internal drives in RAID5 on the Intel SATA/RAID controller for storage. Thanks!
http://www.dvinfo.net/forum/adobe-cr...ly-pp-cs5.html