Expensive Quad Sockets vs. Ubiquitous Dual Sockets
by Johan De Gelas on October 6, 2009 1:00 AM EST- Posted in
- IT Computing
The Number One Reason for Quad Socket
VMmark - which we discussed in great detail here - tries to measure typical consolidation workloads: a combination of a light mail server, database, fileserver, and website with a somewhat heavier java application. One VM is just sitting idle, representative of workloads that have to be online but which perform very little work (for example, a domain controller). In short, VMmark goes for the scenario where you want to consolidate lots and lots of smaller apps on one physical server.
The VMmark scores of the Xeon X5570 make some of the quad socket platforms look silly - once again. The 16 "Shanghai" cores are 13% slower and the 24 "Dunnington" cores are 15% slower than the eight cores with SMT of the X5570. While raw processing power and the excellent optimizations for Hyper-Threading are the main reasons why the X5570 is superior, we suspect it is not the only reason. We'll discuss this in more detail later in this article. Luckily for AMD, the quad Opteron 8435 stays out of the reach of Intel's best server platform.
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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.