The Quad Opteron Alternative

Servers with the newest Intel six-core Xeon hit the market in April. The fastest six-cores Xeons were able to offer up to twice the performance of six-core Opteron “Istanbul”. The reason for this was that the age of the integer core in AMD's Opteron was starting to show. While the floating point part got a significant overhaul in 2007 with the AMD "Barcelona" quad-core chip, the integer part was a tuned version of the K8, launched back in 2003. This was partly compensated by large improvements in the multi-core performance scaling departement: HT-assist, faster CPU interconnects, larger L3 caches, and so on.

To counter this lower per-core performance, AMD's efforts focused on the "Magny-Cours" MCMs that scaled even better thanks to HT 3.0 and four DDR3 memory controllers. AMD’s twelve-core processors were launched at the end of March 2010, but servers based on these “Magny-Cours” Opterons were hard to find. So for a few months, Intel dominated the midrange and high-end server market. HP and Dell informed us that they would launch the "Magny-Cours" servers in June 2010. That is history now, and server buyers have an alternative again for the ubiquitous Xeon Servers.

AMD’s strategy to make their newest platform attractive is pretty simple: be very generous with cores. For example, you get 12 Opteron cores at 2.1GHz for the price of a six-core Xeon 2.66GHz (See our overview of SKUs). In our previous article, we measured that on average, a dual socket twelve-core Opteron is competitive with a similar Xeon server. It is a pretty muddy picture though: the Opteron wins in some applications, the Xeon wins in others. The extra DDR3 memory channel and the resulting higher bandwidth makes the Opteron the choice for most HPC applications. The Opteron has a small advantage in OLAP databases and the virtualization benchmarks are a neck and neck race. The Xeon wins in applications like rendering, OLTP and ERP, although again with a small margin.

But if the AMD platform really wants to lure away significant numbers of customers, AMD will have to do better than being slightly faster or slightly slower. There are many more Xeon based servers out there, so AMD Opteron based servers have to rise above the crowd. And they did: the “core generosity” didn’t end with offering more cores per socket. All 6100 Opterons are quad socket capable: the price per core stays the same whether you want 12, 24 or 48 cores in your machine. AMD says they have “shattered the 4P tax, making 2P and 4P processors the same price.”

So dual socket Opterons servers are ok, offering competitive performance at a slightly lower price, most of the time. Nice, but not a head turner. The really interesting servers of the AMD platforms should be the quad socket ones. For a small price premium you get twice as many DIMM slots and processors as a dual socket Xeon server. That means that a quad socket Opteron 6100 positions itself as a high-end alternative for a Dual Xeon 5600 server. If we take a quick look at the actual pricing of the large OEMs, the picture becomes very clear.

Compared to the DL380 G7 (72GB) speced above, the Dell R815 offers twice the amount of RAM while offering—theoretically—twice as much performance. The extra DIMM slots pay off: if you want 128GB, the dual Xeon servers have to use the more expensive 8GB DIMMs.

Quad Opteron Style Dell
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  • JohanAnandtech - Friday, September 10, 2010 - link

    Thanks, appreciate you took the time to let us know. We went through 5 weeks of intensive testing and my eyes still hurt from looking at the countless excel sheets, with endless power and response time readings. ;-)
  • FourthLiver - Thursday, September 9, 2010 - link

    at the end of page 12, you allude to a performance per watt analysis. looks like you forgot to put it up. i'm chomping at the bit to see those numbers!

    please disregard me if i failed to rtfa correctly. Anandtech is the best; your (all of you collectively) articles are brilliant and correct down to the smallest details. This is another article that was an absolute joy to read. :]
  • JohanAnandtech - Thursday, September 9, 2010 - link

    Well you can't really calculate it, as it depends on the situation. On low load loads, the system that consumes the less, is the winner, on the condition that the response times stay low. But of course, if your systems are running at low load all time, there might be something wrong: you should have bought more RAM and consolidated more VMs per system.

    At higher loads, the power consumption at high load divided by the throughput (vApusmark) is close to the truth. But it is definitely not the performance/watt number for everyone

    It depends on your workloads. The more critical processing power (think response time SLA) is, the more the last mentioned calculation makes sense. The more we are talking about lots of lightly loaded VMs (like authentification servers, fileservers etc.), the more simply looking at the energy consumed at page 12 make sense.
  • mino - Thursday, September 9, 2010 - link

    First, congratulations to a great article !

    Now to the small ammount of mess in there:
    "the CPUs consume more than the ACP ratings that AMD mentions everywhere"

    1) Avegare CPU Power (ACP) is NOT supposed/marketed to represent 100% load power use
    Wikipedia: "The average CPU power (ACP), is a scheme to characterize power consumption of new central processing units under "average" daily usage..."

    2) 122W at the wall and 110W at the CPU ??? Are you telling us the PSU's are 95% along with VRM/power/fans at 95% efficiency ? (0.95*0.95*1.22=1.10)
    . Sorry to spoil the party but that is NOT the case. 122W at wall means 100W at CPU at the most realistically 95W.

    Otherwise a great work. Keep is up!
  • JohanAnandtech - Friday, September 10, 2010 - link

    "1) Avegare CPU Power (ACP) is NOT supposed/marketed to represent 100% load power use
    Wikipedia: "The average CPU power (ACP), is a scheme to characterize power consumption of new central processing units under "average" daily usage...""

    You are right. But what value does it have? As an admin I want to know what the maximum could be realistically (TDP is the absolute maximum for non-micro periods) and if you read between the lines that is more or less what AMD communicated (see their white paper). if it is purely "average", it has no meaning, because average power can be a quite a bit lower as some servers will run at 30% on average, others at 60%.

    These PSU are supposed to be 92-94% efficient and AFAIK the VRMs are at least 90% efficient. So 122 x 0.92 x 0.90 = 101 W.
  • mino - Saturday, September 11, 2010 - link

    Well, I was bit unslept when writing it but anyway. So got a bit harser than should have.

    In my experience the ACP values pretty well represent your average loaded server (<= 80% load). But that is not the point.

    AMD created ACP in a response to the fact that their TDP numbers are conservative while Intel's are optimistic. That was the main cause wery well known to you as well.

    Call me an ass but I certainly do not remember AT bitching about Intel TDPs no bein representative (during last 6 years at least).
    And we all know too well that those NEVER represented the real power use of their boxen nor did they EVER represented what the "TDP" moniker stands for.

    Currently the situation is as such that identical 2P AMD box with 80W ACP has ~ the same power requirements as 2P Intel box with 80W TDP. You have just proven that.

    Therefore I believe it would be fair to stop bitching about AMD (or Intel) cheating in marketing (both do) and just say whether the numbers are comparable or not.
    Arguing about spin wattage is not really needed.
  • JohanAnandtech - Monday, September 13, 2010 - link

    "Arguing about spin wattage is not really needed. "

    I have to disagree. The usual slogan is "don't look at TDP, look at measurements". What measurments? The totally unrealistic SPECpower numbers?

    It is impossible for review sites to test all CPUs. So it is up to vendors to gives us a number that does not have to be accurate on a few percent, but that let us select CPUs quickly.

    Customers should have one number that allows them to calculate worst case numbers which are realistic (heavily load webserver for example, not a thermal virus). So all CPU vendors should agree on a standard. That is not bitching, but is a real need of the sysadmins out there.
  • mino - Thursday, September 9, 2010 - link

    One thing I would love to see is having the lowest end HP server put to its paces.
    So far it seems to us a the best option for vCenter hosting in small environments (with FT Vm's hosting vCenter).

    Maybe even run 1-tile vAPUS (v1? perhaps) on it ?
  • m3rdpwr - Thursday, September 9, 2010 - link

    I would have prepared to have had the DL385 G7 compared.
    They can be had with 8 and 12 core CPU's.

    We have close to 200 HP servers of all models, rack and blades.
    Many running vm in our Data Center.

    -Mario
  • duploxxx - Friday, September 10, 2010 - link

    same here, we moved also to 385g7 with the new 8-12core cpu's, Nice servers with huge core count since we never run more vCPU then pCPU in a system. Dell 815 looks like a good solution also, it was mentioned in the review the BL685 and DL585 are way more expensive.

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