Electricity Bill

Having one PSU power two nodes should make sure that the 900W PSU is never working at a very low load, and thus at its lowest efficiency. Using motherboards with only the features that are really necessary and a PSU that is "more than 90%" efficient should also help. On the flipside, a 1U server with 16 cores is harder to cool than two 1U servers with 8 cores.


So how much power can you save with Supermicro's Twin compared to two 1U servers? We decided to find out with Supermicro's 1U 6015b-8+ server. This server has a slightly less efficient 700W PSU, "up to 85% efficient", which is still better than the average PSU in the 1U market. Also, the 6015b+8+ features a U320SCSI controller and one SCSI320 disk which adds about 10-15W.

We tested for 400 seconds (the x-axis).


To sum up our findings:
  • A 1U server with 85% efficient PSU needs +/- 230 W
  • The Twin 1U server with 1 Node powered on needs +/- 213 W
  • Twin 1U server with both nodes working uses +/- 330 W
We can conclude that:
  • The second node adds only 55% more power
  • In comparison with 2x 1U servers, we save about 130W or about 30% thanks to Twin 1U system
Of course it is rare that a server runs at maximum power. Let us see how much power the different systems consume running idle. We tested for about 100 seconds.


To get a better idea, we summarized the averages in the table below:

Average Power Use
Configuration Idle (Watt) Full Load (Watt)
Twin 1U: 1 node 160 213
Twin 1U: 2 nodes 271 330
Power increase 1 to 2 node 69% 55%
Normal 1U 200 230
2 x Normal 1U 400 460
Power savings compared to "Normal 1U" 129 130

Even if we take into account that two "normal" 1U servers would probably consume a bit less (as it gets harder to keep them at 100% load), and even if we take into account the fact that the SCSI controller and disk increase the power consumption by about 10W, we think it is safe to say that each 1U Twin server saves about 100W compared to two "normal" 1U servers. Mission accomplished for the Supermicro PSU engineers.

3DSMax 9 Backburner Rendering Analysis
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  • JohanAnandtech - Monday, May 28, 2007 - link

    Those DIMM slots are empty :-)
  • yacoub - Monday, May 28, 2007 - link

    ohhh hahah thought they were filled with black DIMMs :D
  • yacoub - Monday, May 28, 2007 - link

    Also on page 8:

    quote:

    In comparison, with 2U servers, we save about 130W or about 30% thanks to Twin 1U system

    You should remove that first comma. It was throwing me off because the way it reads it sounds like the 2U servers save about 130W but then you get to the end of the sentence and realize you mean "in comparison with 2U servers, we save about 130W or about 30% thanks to Twin 1U". You could also say "Compared with 2U servers, we save..." to make the sentence even more clear.

    Thanks for an awesome article, btw. It's nice to see these server articles from time to time, especially when they cover a product that appears to offer a solid TCO and strong comparative with the competition from big names like Dell.
  • JohanAnandtech - Monday, May 28, 2007 - link

    Fixed! Good point
  • gouyou - Monday, May 28, 2007 - link

    The part about infiniband's performance much better as you increase the number of core is really misleading.

    The graph is mixing core and nodes, so you cannot tell anything. We are in an era where a server has 8 cores: the scaling is completely different as it will depend less on the network. BTW, is the graph made for single core servers ? dual cores ?
  • MrSpadge - Monday, May 28, 2007 - link

    Gouyou, there's a link called "this article" in the part on InfiniBand which answers your question. In the original article you can read that they used dual 3 GHz Woodcrests.

    What's interesting is that the difference between InfiniBand and GigE is actually more pronounced for the dual core Woodcrests compared with single core 3.4 GHz P4s (at 16 nodes). The explanation given is that the faster dual core CPUs need more communication to sustain performance. So it seems like their algorithm uses no locality optimizations to exploit the much faster communication within a node.

    @BitJunkie: I second your comment, very nice article!

    MrS
  • BitJunkie - Monday, May 28, 2007 - link

    Nice article, I'm most impressed by the breadth and the detail you drilled in to - also the clarity with which you presented your thinking / results. It's always good to be stretched and great example of how to approach things in structured logical way.

    Don't mind the "it's an enthusiast site" comments. Some people will be stepping outside their comfort zone with this and won't thank you for it ;)
  • JohanAnandtech - Monday, May 28, 2007 - link

    Thanks, very encouraging comment.

    And I guess it doesn't hurt the "enthusiast" is reminded that "pcs" can also be fascinating in another role than "Hardcore gaming machine" :-). Many of my students need the same reminder: being an ITer is more than booting Windows and your favorite game. My 2-year old daughter can do that ;-)
  • yyrkoon - Monday, May 28, 2007 - link

    It is however nice to learn about InfiniBand. This is a technology I have been interrested in for a while now, and was under the impression was not going to be implemented until PCIe v2.0 (maybe I missed something here).

    I would still rather see this technology in the desktop class PC, and if this is yet another enterprise driven technology, then people such as myself, who were hoping to use it for decent home networking(remote storage) are once again, left out in the cold.
  • yyrkoon - Monday, May 28, 2007 - link

    quote:

    And I guess it doesn't hurt the "enthusiast" is reminded that "pcs" can also be fascinating in another role than "Hardcore gaming machine" :-). Many of my students need the same reminder: being an ITer is more than booting Windows and your favorite game. My 2-year old daughter can do that ;-)


    And I am sure every gamer out there knows what iSCSI *is* . . .

    Even in 'IT' a 16 core 1U rack is a specialty system, and while they may be semi common in the load balancing/failover scenario(or maybe even used extensively in paralell processing, yes, and even more possible uses . . .), they are still not all that common comparred to the 'standard' server. Recently, a person that I know deployed 40k desktops/ 30k servers for a large company, and would'nt you know it, not one had more than 4 cores . . . and I have personally contracted work from TV/Radio stations(and even the odd small ISP), and outside of the odd 'Toaster', most machines in these places barely use 1 core.

    I too also find technologies such as 802.3 ad link aggregation, iSCSI, AoE, etc interresting, and sometimes like playing around with things like openMosix, the latest /hottest Linux Distro, but at the end of the day, other than experimentation, these things typically do not entertain me. Most of the above, and many other technologies for me, are just a means to an end, not entertainment.

    Maybe it is enjoyable staring at a machine of this type, not being able to use it to its full potential outside of the work place ? Personally I would not know, and honestly I really do not care, but if this is the case, perhaps you need to take notice of your 2 year old daughter, and relax once in a while.

    The point here ? The point being: pehaps *this* 'gamer' you speak of knows a good bit more about 'IT' than you give him credit for, and maybe even makes a fair amount of cash at the end of the day while doing so. Or maybe I am a *real* hardware enthusiast, who would rather be reading about technology, instead of reading yet another 'product review'. Especially since any person worth their paygrade in IT should already know how this system (or anything like) is going to perform beforehand.

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