AMD back in the quad socket race

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• tshen83 - Wednesday, April 9, 2008 - link

  Is indeed more impressive compared to Intel's simply because of the memory controller and its scalability.
  
  However, one thing must be said that 4S market will be dying off because 2S systems are the most economical from a price/watt/dollar perspective. In the 2S market, Intel's Xeons are priced in parity compared to its Core 2 products which makes it very attractive. Let's face it, google is buying 2S systems from Intel, the decision must be right.
  
  Scalability now is solved by software such as clustering techniques: Hadoop and Google Map Reduce programming paradigms.

• Starglider - Thursday, April 10, 2008 - link

  > However, one thing must be said that 4S market will be
  > dying off because 2S systems are the most economical from
  > a price/watt/dollar perspective.
  
  Maybe if you have copious rackspace. For may users rackspace is at a premium; decemt co-lo is expensive. We're about to put in a couple of new 16-core servers, possibly Opterons (which is why I'm looking forward to this review). The reason is that it's the maximum CPU power you can cram into 1U (without going to blades, which aren't appropriate for us ATM).

• tshen83 - Thursday, April 10, 2008 - link

  "Maybe if you have copious rackspace. For may users rackspace is at a premium"
  
  So you pay a 4x premium on the CPUs to save 1U of space? That's about the best argument I have heard.
  
  If you are so cash strapped to have to put 16 CPUs in 1U, you obviously have no idea about data center cooling requirements. Not many data centers currently give you that density. A 4S quad Opteron server would draw about 800-1000W(125W*4 + 10W per stick of memory *16 sticks + 12W per hard drive *8 drives) That is between 6-8A of current per 1U. There is many data center I am aware of that will provision 300A+ per rack(40U* 8A per U) Most datacenters will give you 20A for the whole rack. So you can probably put 3 of those systems in a entire rack which means the 1U meaningless.

• joekraska - Sunday, April 13, 2008 - link

  > Most datacenters will give you 20A for the whole rack.
  
  Mmmm. Older data centers might feature dual 208 20A or dual 115 30A. But the trend is now away from this.
  
  Defaults are to dual 208 30A, and that's only for "low density".
  
  For high density, you'll see AT LEAST four L6-30's above the rack now, and you'll start seeing two to four L21-30 (30A 3 phase) or even 35A 3 phase to the rack quite frequently with newer high density deployments.
  
  Frankly, powering high density deployments is getting so challenging, that I'm expecting > 35A 3 phase within 24 months. How we avoid killing data center facilities workers, I haven't figgered out yet. :-)
  
  Anyway, whichever poster said the cost economics aren't there for 4S servers was correct. Up until the present. For example, if you are buying a Dell R900 over two Dell 2950iii's to run virtual servers you are making a grave financial error. It will, however, be interesting to see if AMD's newer system can change that equation.
  
  Joe.
  

• DigitalFreak - Thursday, April 10, 2008 - link

  And the BS keeps on a-comin.

• Creig - Thursday, April 10, 2008 - link

  I think you need to shut up now...

• Starglider - Thursday, April 10, 2008 - link

  > So you pay a 4x premium on the CPUs to save 1U of space?
  
  The 8-socket Opterons are between two and three times as expensive as the 2-socket ones depending on model.
  
  > A 4S quad Opteron server would draw about 800-1000W (125W*4
  > + 10W per stick of memory *16 sticks + 12W per hard drive
  > *8 drives)
  
  That is ridiculous. 125W is a theoretical maximum, in practice even loaded CPUs are unlikely to exceed 80W. Registed DDR2 draws about 4 watts a stick, not 10 (were you thinking of FB-DIMM). I doubt it's physically possible to get 8 3.5" drives into a 1U case along with a 4S motherboard; the most I've seen is 4, though 12W is a reasonable loaded power draw. Including motherboard and fan power draw and power supply inefficiency, that's about 600W for a fully loaded server, which is two and a half amps (yes, I live in a country with a sane mains supply voltage). Of course full load is only experienced for a few hours a day; most of the time the power draw would be down below 300W.
  
  > Most datacenters will give you 20A for the whole rack.
  
  I don't know what worthless provider you're using that can only manage 2.5 KW/rack, but ours allows 400 watts per 1U server. We may have to ask for an upgrade to that if low voltage chips aren't an option.

• Justin Case - Wednesday, April 9, 2008 - link

  Assuming you need the processing power of 16 CPU cores, how is a single 16-core system less efficient per watt / dollar than two separate 8-core systems? A single "big" system lets you dynamically allocate resources (either within a single OS or through virtualization) and run much more efficiently. Not to mention it's cheaper (the only element that's more expensive is the main board, everything else costs the same, and doesn't need to be duplicated).
  
  As to "scalability as been solved", maybe you should tell that to all the "morons" in the HPC field that are still using (and planning, and designing, and putting together) supercomputers...?

• JohanAnandtech - Wednesday, April 9, 2008 - link

  Google is a special case, as most of the applications they are running have almost infinite scalability. However, a lot of servers are also sold to consolidate smaller ones on. 4 socket systems might then be much more interesting than buying dual socket ones. You have twice the memory, twice the CPU power and a whole of other "big box" advantages such easier serviceability (adding another network controller or Disk controller) etc.
  
  4-socket have probably a good future ahead thanks to virtualization and the fact that they also gotten smaller: you get 4 socket systems in 2U (with lots of expandability), 1U and even blades.

• tshen83 - Wednesday, April 9, 2008 - link

  Johan:
  
  Your argument that Google and facebook's decision to buy 2S systems is a special case then you are seriously mistaken. 4S systems have a very small niche market.
  
  That niche market is for customers who have dependence on non-clustered software packages that can scale vertically to 16 cores. There aren't many types of software that cannot cluster but can scale linearly on 16 cores. Database and Virtualization are the only two types where it can be scaled vertically.
  
  For database apps, ram rules, and memcache basically took care of distributed memory cache for database. So having extremely large amount of memory locally on the DB server is now mitigated. Plus, given the pricing on the 4S CPUs, it is better to buy four 2S nodes and use DB cluster(MySQL NBD Engine) or simply Master-Slave configuration to handle load than having a single one. You needed redundancy anyways.
  
  For virtualization, I have not seen any virtualization software package that can virtualize multiple-CPU systems reliably, simply due to CPU cycle contention issues. What I mean by that is that, ideally, you want to be able to virtualize 16 systems, each with 16 CPUs, on a 16CPU system. In that setup, every virtualized system can get access to maximum 16 cores, so every virtualized system can potentially take over the entire server should the load increase. Right now, all virtualization software are good at virtualizing 1-CPU machine as a single thread on the host OS scheduler. Even VMware's 2CPU support is buggy, and you will notice performance degradations when the total virtualized CPU is greater than the physical CPUs you have. That limits the potential power of the virtualized system.
  
  On the hardware side, you failed to mention the nonlinear scaling of the Opterons at the 4S level(Intel too for that matter). The only chipset I am aware of that can support 4S and 8S Opterons are from Nvidia and as far as I know, is HyperTransport 1 based. You need HyperTransport 3's bandwidth to be able to scale Opterons to 4S linearly.