# How much power...



## Steven F (Nov 17, 2014)

How much power would be needed for 39 x dual L5420s and 3 switches? I've heard some pretty varying estimates, so I thought I'd ask you all, who may have actual experience.


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## serverian (Nov 17, 2014)

How many memory sticks at what voltage?

How many drives?

What type of drives?

Addon cards?

What kind of switches?


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## Munzy (Nov 17, 2014)

How much utilization?

Just CPU wise:

(39 servers) x (2 for each cpu per server) x (50 watts, based on the TDP) = ~3900 watts.


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## fizzyjoe908 (Nov 17, 2014)

Due to 80% power usage policies most everywhere, you will need about 60 amps @ 110V for that setup.


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## HalfEatenPie (Nov 17, 2014)

A ton.

A dedicated hamster-on-wheels is probably needed in addition to that.


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## ChrisM (Nov 17, 2014)

Steven F said:


> How much power would be needed for 39 x dual L5420s and 3 switches? I've heard some pretty varying estimates, so I thought I'd ask you all, who may have actual experience.





fizzyjoe908 said:


> Due to 80% power usage policies most everywhere, you will need about 60 amps @ 110V for that setup.


With these servers and moderate usage with the fans on max capacity they use around 1-1.2 amps each and @fizzyjoe908 is correct about the 80% so you would need around 60amps.


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## HalfEatenPie (Nov 17, 2014)

Chris Miller said:


> With these servers and moderate usage with the fans on max capacity they use around 1-1.2 amps each


At what volt HM??!!!

Oh... 110V.

Well.... So... How's the weather today?


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## ChrisM (Nov 17, 2014)

HalfEatenPie said:


> At what volt HM??!!!
> 
> 
> Oh... 110V.
> ...


Pretty good. Snowy with a chance of death and despair..... They are talking about 12+ inches of snow with 40mph (Gusting 60) winds. 



All this talk about Power and weather reminds me I really need to check on my backup generator incase the power goes out...


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## TurnkeyInternet (Nov 18, 2014)

Your minimum will be Dual 30 Amp @ 110 V breakers and power strips (60 amps @ 110 V).  If you have lots of disks/ram - you could push over that though (or be too close to the 80% typical breaker budget to fit within Dual 30 Amp @ 110 V).  If you go with 208V (if your datacenter can supply it) you may do better, especially if they offer metered power (actual usage on KWh).


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## qps (Nov 19, 2014)

Do these L5420 systems use fully-buffered DIMMs?  If so, don't bother.  The power cost will be so high that it isn't worth it.  Many data centers won't let you get that dense in a cabinet without an additional cooling charge.

If they are DDR2 ECC, it depends on which model server.  We've used most of them, so if you post the specifics, we can advise what to expect.


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## Steven F (Nov 19, 2014)

qps said:


> Do these L5420 systems use fully-buffered DIMMs?  If so, don't bother.  The power cost will be so high that it isn't worth it.  Many data centers won't let you get that dense in a cabinet without an additional cooling charge.
> 
> If they are DDR2 ECC, it depends on which model server.  We've used most of them, so if you post the specifics, we can advise what to expect.


Also the amount of DIMMs matters, as well. 8 sticks versus 4 sticks is a *huge* difference, that can be like 40 watts. I'm waiting to hear back about the RAM, though, because I don't know the amount of sticks or the exact type.

The RAM is listed as PC2-5300P.


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## qps (Nov 19, 2014)

Steven F said:


> The RAM is listed as PC2-5300P.


This is DDR2 ECC.  Most of our Dual L5420 with 16GB PC2-5300P (4x 4GB) run at about 1 amp on 120v, but fan speed can make a big difference.  If you have the fans running full blast, you may see significantly higher numbers.


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## Steven F (Nov 19, 2014)

qps said:


> This is DDR2 ECC.  Most of our Dual L5420 with 16GB PC2-5300P (4x 4GB) run at about 1 amp on 120v, but fan speed can make a big difference.  If you have the fans running full blast, you may see significantly higher numbers.


Awesome. See, your factual information is significantly lower than the estimates I've seen. So, I'm guessing that we should be fine with the 2 x 30 amp circuits. I really appreciate it.


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## devonblzx (Dec 7, 2014)

Steven F said:


> Awesome. See, your factual information is significantly lower than the estimates I've seen. So, I'm guessing that we should be fine with the 2 x 30 amp circuits. I really appreciate it.


Did you already get this setup?  I just came across this and noticed you didn't include brand or model or hard drive setup.  It makes a big difference.

Our Supermicro L5420s run at or below 1amp 120v with SSDs.  Our HP and Dells use around 1.5-1.6A with SSDs and closer to 2A with 4 hard drives.  Keep in mind, 4 hard drives use around 30w idle, 40w during use.

Netgears gigabit switches use around 15-40w depending on the model.  HP procurve switches use between 1-2A.  Cisco switches are too plentiful to give an estimate.

So depending on the brands and hard drive setup, 60A may not be enough.  You should get one as a demo before getting things set up and use a Kill-a-watt meter on it.  Those little things are great.


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## MartinD (Dec 8, 2014)

devonblzx said:


> Netgears gigabit switches use around 15-40w depending on the model.  HP procurve switches use between 1-2A.  Cisco switches are too plentiful to give an estimate.


I presume you're talking 120v here? I use quite a few procurves here and they use nowhere NEAR that amount of juice.


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## Steven F (Dec 8, 2014)

devonblzx said:


> Did you already get this setup?  I just came across this and noticed you didn't include brand or model or hard drive setup.  It makes a big difference.
> 
> Our Supermicro L5420s run at or below 1amp 120v with SSDs.  Our HP and Dells use around 1.5-1.6A with SSDs and closer to 2A with 4 hard drives.  Keep in mind, 4 hard drives use around 30w idle, 40w during use.
> 
> ...



Yeah, we're getting power usage stats before we order, but sometimes the numbers just seem really low.


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## devonblzx (Dec 8, 2014)

MartinD said:


> I presume you're talking 120v here? I use quite a few procurves here and they use nowhere NEAR that amount of juice.


Yeah, 120v.  Most are rated between 100 and 200W.  What model are you running?  I'm sure newer models are lower power, but most people get older models off ebay since they work fine.


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## devonblzx (Dec 8, 2014)

MartinD said:


> I presume you're talking 120v here? I use quite a few procurves here and they use nowhere NEAR that amount of juice.


You're right, atleast for the newer models.  The older models could easily produce over 1A, but just looked up the HP 1910 48G and its rated 60W.  Big improvement on the older models.


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