Expensive Quad Sockets vs. Ubiquitous Dual Sockets
by Johan De Gelas on October 6, 2009 1:00 AM EST- Posted in
- IT Computing
The answer was simple: "You cannot compare a truck with a sports car." The question? "What is point of the hex-core Xeon MP now that we have servers based on the Xeon 5500 series?" The excellent performance of the new Xeon DP platform has put Intel's own quad socket platform in an uneasy spot and the marketing people now have to resort to "fuzzy logic" to combat the feeling that the Xeon MP platform is obsolete since the end of March 2009. Comparing the dual socket Nehalem servers with sports cars and the heavy quad socket "Dunnington" systems with trucks might look like a decent analogy at first, but both the DP and MP platform are made for the same reason: do your processing work. There is nothing that prevents you from using a Xeon DP X5550 server instead of a Xeon 7460 one as a database backend: they can perform the same tasks. However, moving your furniture with a Lamborghini instead of a truck might prove to be quite a challenge.
Does it matter for you, the IT professional? Yes, and the reason is once again… virtualization. Choosing between a dual and quad socket server used to be simple: use the latter for the heavy backend applications, the former for everything else. But do you build your virtual infrastructure on top of quad socket or dual socket machines? The dual socket servers are much cheaper than the quads, you can easily get two and still save some money compared to buying a quad machine. However, two dual machines have four power supplies if you want redundancy, and when running 10 critical applications on a machine redundancy is something you cannot afford to ignore. Most quad socket machines are more redundant and reliable. Since the quad market is less ruled by price/performance and slower to evolve, manufacturers can afford to spend more time and money working on the reliability of their machines. One 2U quad machine will also have more expansion slots than two 1U dual socket machines.
Do you get a few quad socket machines or (slightly less than) twice as many dual socket servers? It is not as clear cut a decision as it used to be. This article will compare the power and performance of the current AMD and Intel quad and dual platforms, giving you some of the information you need to make a well informed decision. Please share your own experiences with the dual and quad socket question, we are eagerly awaiting them.
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rbbot - Tuesday, October 6, 2009 - link
Surely the high price of 8GB Dimms isn't going to last very long, especially with Samsung about to launch 16GB parts soon.Calin - Wednesday, October 7, 2009 - link
8GB DIMMs have two markets: one would be upgrade from 4GB or 2GB parts in older servers, the other would be more memory in cheaper servers. As the demand can be high, it all depends on the supply - and if the supply is low, prices are high.So, don't count on the price of 8GB DIMMs to decrease soon
Candide08 - Tuesday, October 6, 2009 - link
One performance factor that has not improved much over the years is the decrease in percentage of performance gains for additional cores.A second core adds about 60% performance to the system.
Third, fourth, fifth and sixth cores all add lower (decreasing) percentages of real performance gains - due to multi-core overhead.
A dual socket dual core system (4 processors) seems like the sweet spot to our organization.
Calin - Wednesday, October 7, 2009 - link
If your load is enough to fit into four processors, then this is great. However, for some, this level of performance is not enough, and more performance is needed - even if paying four times as much for twice as much performancehifiaudio2 - Tuesday, October 6, 2009 - link
FYI the R710 can have up to 192gb of ram...12x16GB
not cheap :) but possible
JohanAnandtech - Tuesday, October 6, 2009 - link
at $300 per GB, or the price of 2 times 4 GB DIMMs, I don't think 16 GB DIMMs are going to be a big success right now. :-)wifiwolf - Wednesday, October 7, 2009 - link
for at least 5 years you meanmamisano - Tuesday, October 6, 2009 - link
Great article, just have a question about the power supplies. Why do the quad-core servers need a 1200W PSU if the highest measured load was 512W? I know you would like to have some head-room but it looks to me that a more efficient 750 - 900W PSU may have provided better power consumption results... or am I totally wrong? :)JarredWalton - Tuesday, October 6, 2009 - link
Maximum efficiency for most PSUs is obtains at a load of around 40-60% (give or take), so if you have a server running mostly under load you would want a PSU rated at roughly twice the load power. (Plus a bit of headroom, of course.)JohanAnandtech - Wednesday, October 7, 2009 - link
Actually, the best server PSUs are now at maximum efficiency (+/- 3%) between 30 and 95% load.For example:
http://www.supermicro.com/products/powersupply/80P...">http://www.supermicro.com/products/powersupply/80P...
And the reason why our quads are using 1000W PSUs (not 1200) is indeed that you need some headroom. We do not test the server with all DIMM slots filled and you also need to take in account that you need a lot more power when starting up.