X-Gene 1, Atom C2000 and Xeon E3: Exploring the Scale-Out Server World
by Johan De Gelas on March 9, 2015 2:00 PM ESTQuick Overview of the SoCs
In this review, we compare four different SoCs:
- Intel's Xeon E3-1240 v3 3.4GHz
- Intel's Xeon E3-1230L v3 1.8GHz
- Intel's Xeon E3-1265L v2 2.5GHz
- Intel's Atom C2750 2.4GHz
- AppliedMicro's X-Gene 1 2.4GHz
We have discussed the Xeon E3-1200 v3, Atom C2000, and X-Gene in more detail in our previous article. What follows is a quick discussion of why we tested these specific SKUs.
The Intel Xeon E3-1240 v3 is a speedy (3.4GHz, eight threads) Xeon E3 that is still affordable and has a decent TDP (69W). If you want a 6% higher clock (3.6GHz), Intel charges you 2.3X more. The Xeon E3-1240 v3 has an excellent performance per dollar ratio.
The Xeon E3-1230L v3 paper specs are incredible: eight cores that can boost to up to 2.8GHz (with a base clock of 1.8GHz) and a very low TDP of 25W. To see how much progress Intel has made, we compare it with the 45W Intel E3-1265L v2 at 2.5GHz based on the Ivy Bridge core. Will the Haswell core be enough to overcome the 700MHz (1.8 vs 2.5GHz) lower clock speed, which is necessary to make the chip work with a very low 25W TDP? How does this very low power Xeon with the brawny core compare to the Atom C2750?
The Atom C2750 is Intel's fastest Atom-based Xeon. We are very curious to see if there are applications where the eight lean cores can outperform the four wide cores of the Xeon E3.
And last but not least, the X-Gene 2.4GHz, the first server SoC incarnation of the ARMv8-A or AArch64 instruction set. The X-Gene has twice as many memory channels and can support twice as many DIMM slots as its Intel competitors. The cache architecture is a mix of the Atom C2000 and Xeon E3. Just like the Atom, two cores share a smaller L2 cache (256KB vs 1MB). And like the Xeon E3 (and unlike the Atom C2000), the X-Gene also has access to and 8MB L3 cache. Less positive is the antiquated 40nm production process and the fact that power management is much less sophisticated than Intel's solutions. The result is a relatively high 40W TDP.
While not every application was available on the X-Gene, we gathered enough datapoints to do a meaningful comparison. Where will the first productized ARMv8 chip land? Will it be an Atom C2000 or Xeon E3 killer, or neither? What kind of applications run well, and what kind of applications are still running much faster on a x86 chip?
We've added a few CPUs/SoCs to further improve the comparison. We've thrown in the Atom N2800 to mimic one of the worst Intel server CPUs ever (well, maybe "Paxville MP" was worse), the Atom S1260. The Xeon X5470 ("Harpertown", Penryn architecture) is also featured just to satisfy our curiosity and show how much performance has evolved. To understand the performance of the different SoCs, we should also take into account that the Intel chips almost always run at a higher clock speed than the advertised clock speed, thanks to Turbo Boost.
| Overview of Clock Speeds | ||||
| SoC | Max. Turbo Boost | Turbo Boost with Two Cores |
Turbo Boost with All Cores |
TDP |
| Xeon E3-1240v3 3.4 | 3800 | 3600 | 3600 | 80W |
| Xeon E3-1230Lv3 1.8 | 2800 | 2300 | 2300 | 25W |
| Xeon E3-1220v2 3.1 | 3500 | 3500 | 3300 | 69W |
| Xeon E3-1265Lv2 2.5 | 3500 | 3400 | 3100 | 45W |
| Atom C2750 2.4 | 2600 | 2600 | 2400 | 20W |
| X-Gene 1 2.4 | N/A | N/A | 2400 | 40W |
The 1.8GHz clock of the 25W TDP Xeon E3-1230L v3 may seem pretty low, but in reality the chip clocks at 2.3GHz and more. Single-threaded performance is even better with a top speed of 2.8GHz. The same is true for the Xeon E3-1265L v2, which has an even greater delta between the advertised clock speed (2.5GHz) and the actual clock speed (3.1 – 3.4GHz) when we run our benchmarks.
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JohanAnandtech - Tuesday, March 10, 2015 - link
Thanks! It is been a long journey to get all the necessary tests done on different pieces of hardware and it is definitely not complete, but at least we were able to quantify a lot of paper specs. (25 W TDP of Xeon E3, 20W Atom, X-Gene performance etc.)enzotiger - Tuesday, March 10, 2015 - link
SeaMicro focused on density, capacity, and bandwidth.How did you come to that statement? Have you ever benchmark (or even play with) any SeaMicro server? What capacity or bandwidth are you referring to? Are you aware of their plan down the road? Did you read AMD's Q4 earning report?
BTW, AMD doesn't call their server as micro-server anymore. They use the term dense server.
Peculiar - Tuesday, March 10, 2015 - link
Johan, I would also like to congratulate you on a well written and thorough examination of subject matter that is not widely evaluated.That being said, I do have some questions concerning the performance/watt calculations. Mainly, I'm concerned as to why you are adding the idle power of the CPUs in order to obtain the "Power SoC" value. The Power Delta should take into account the difference between the load power and the idle power and therefore you should end up with the power consumed by the CPU in isolation. I can see why you would add in the chipset power since some of the devices are SoCs and do no require a chipset and some are not. However, I do not understand the methodology in adding the idle power back into the Delta value. It seems that you are adding the load power of the CPU to the idle power of the CPU and that is partially why you have the conclusion that they are exceeding their TDPs (not to mention the fact that the chipset should have its own TDP separate from the CPU).
Also, if one were to get nit picky on the power measurements, it is unclear if the load power measurement is peak, average, or both. I would assume that the power consumed by the CPUs may not be constant since you state that "the website load is a very bumpy curve with very short peaks of high CPU load and lots of lows." If possible, it may be more beneficial to measure the energy consumed over the duration of the test.
JohanAnandtech - Wednesday, March 11, 2015 - link
Thanks for the encouragement. About your concerns about the perf/watt calculations. Power delta = average power (high web load measured at 95% percentile = 1 s, an average of about 2 minutes) - idle power. Since idle power = total idle of node, it contains also the idle power of the SoC. So you must add it to get the power of the SoC. If you still have doubts, feel free to mail me.jdvorak - Friday, March 13, 2015 - link
The approach looks absolutely sound to me. The idle power will be drawn in any case, so it makes sense to add it in the calculation. Perhaps it would also be interesting to compare the power consumed by the differents systems at the same load levels, such as 100 req/s, 200 req/s, ... (clearly, some higher loads will not be achievable by all of them).Johan, thanks a lot for this excellent, very informative article! I can imagine how much work has gone into it.
nafhan - Wednesday, March 11, 2015 - link
If these had 10gbit - instead of gbit - NICs, these things could do some interesting stuff with virtual SANs. I'd feel hesitant shuttling storage data over my primary network connection without some additional speed, though.Looking at that moonshot machine, for instance: 45 x 480 SSD's is a decent sized little SAN in a box if you could share most of that storage amongst the whole moonshot cluster.
Anyway, with all the stuff happening in the virtual SAN space, I'm sure someone is working on that.
Casper42 - Wednesday, April 15, 2015 - link
Johan, do you have a full Moonshot 1500 chassis for your testing? Or are you using a PONK?