Next Stop: the Uncore

Continuing with our review of Haswell architecture, let's again take a step back and use the Xeon 5500 as our reference point. The Xeon 5500 is based on the "Nehalem" architecture, and it helped Intel become dominant in the server market. Before the Xeon 5500, AMD's Opteron was still able to outperform the Xeons in quite a few applications (HPC and virtualization for example), even by significant margins. That changed with Nehalem, so the Xeon 5500 is a good reference point.

7-zip Benchmark – Single Threaded

The 27% cumultative IPC (integer only) improvement of Haswell mentioned is more than just theory: Anand's review of the desktop Haswell CPUs confirmed this. The Haswell Core i7-4770k at the same clock speed is about 21% faster than Nehalem. Now that is below the promised 27% performance increase, but 7-zip is among the applications known to have very low IPC.

Let's go back to the server world. Instead of increasing the clock speeds, clock speeds have declined from 2.93-3.2GHz (Xeon 5500) to 2.3-2.6GHz for the latest high-end parts. However, when Turbo Boost is enabled, 2.8 – 3.1GHz is possible with all cores active. So the clock speed of the high end server CPUs is actually 5 to 20% lower and not 10% higher as in the desktop space. The gains Intel has made in IPC are thus partly negated by slightly lower clock speeds.

Clock speed has clearly been traded in for more cores in most of server SKUs. But the additional cores can prove extremely useful. The SAP S&D application – one of the best industry benchmarks – runs about three times faster (see further) on the latest Xeon E5-2699 v3 than on the Xeon 5500.

This clearly puts into perspective how important the uncore part is for Xeons. The uncore parts makes the difference between a CPU that is only good at running a few handpicked benchmarks (like SPECint rate) but fails to achieve much in real applications, vs. an attractive product that can lower the IT costs by running more virtual machines and offering services to more users.

Refresher: the Haswell Core The Magic Inside the Uncore
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  • MorinMoss - Friday, August 9, 2019 - link

    Hello from 2019.
    AMD has a LOT of ground to make up but it's a new world and a new race
    https://www.anandtech.com/show/14605/the-and-ryzen...
    Reply
  • Kevin G - Monday, September 8, 2014 - link

    As an owner of a dual Opteron 6376 system, I shudder at how far behind that platform is. Then I look down and see that I have both of my kidneys as I didn't need to sell one for a pair of Xeons so I don't feel so bad. For the price of one E5-2660v3 I was able to pick up two Opteron 6376's. Reply
  • wallysb01 - Monday, September 8, 2014 - link

    But the rest of the system cost is about the same. So you get 1/2 the performance for a 10% discount. YEPPY! Reply
  • Kevin G - Monday, September 8, 2014 - link

    Nope. Build price after all the upgrades over the course of two years is some where around $3600 USD. The two Opterons accounted for a bit more than a third of that price. Not bad for 32 cores and 128 GB of memory. Even with Haswell-E being twice as fast, I'd have to spend nearly twice as much (CPU's cost twice as much as does DDR4 compared to when I bought my DDR3 memory). To put it into prespective, a single Xeon E5 2999v3 might be faster than my build but I was able to build an entire system for less than the price Intel's flagship server CPU.

    I will say something odd - component prices have increased since I purchased parts. RAM prices have gone up by 50% and the motherboard I use has seemingly increased in price by $100 due to scarcity. Enthusiast video card prices have also gotten crazy over the past couple of years so a high end video card is $100 more for top of the line in the consumer space.
    Reply
  • wallysb01 - Tuesday, September 9, 2014 - link

    Going to the E5 2699 isn’t needed. A pair of 2660 v3s is probably going to be nearly 2x as fast the 6376, especially for floating point where your 32 cores are more like 16 cores or for jobs that can’t use very many threads. True a pair of 2660s will be twice as expensive. On a total system it would add about $1.5K. We’ll have to wait for the workstation slanted view, but for an extra $1.5K, you’d probably have a workstation that’s much better at most tasks. Reply
  • Kevin G - Friday, September 12, 2014 - link

    Actually if you're aiming to double the performance of a dual Opteron 6376, two E5-2695v3's look to be a good pick for that target according to this review. A pair of those will set you pack $4848 which is more than what my complete system build cost.

    Processors are only one component. So while a dual Xeon E5-2695v3 system would be twice as fast, total system cost is also approaching double due to memory and motherboard pricing differences.
    Reply
  • Kahenraz - Monday, September 8, 2014 - link

    I'm running a 6376 server as well and, although I too yearn for improved single-threaded performance, I could actually afford to own this one. As delicious as these Intel processors are, they are not priced for us mere mortals.

    From a price/performance standpoint, I would still build another Opteron server unless I knew that single-threaded performance was critical.
    Reply
  • JDG1980 - Tuesday, September 9, 2014 - link

    The E5-2630 v3 is cheaper than the Opteron 6376 and I would be very surprised if it didn't offer better performance. Reply
  • Kahenraz - Tuesday, September 9, 2014 - link

    6376s can be had very cheaply on the second-hand market, especially bundled with a motherboard. Additionally, the E5-2630 v3 requires both a premium on the board and DDR4 memory.

    I'd wager you could still build an Opteron 6376 system for half or less.
    Reply
  • Kevin G - Tuesday, September 9, 2014 - link

    It'd only be fair to go with the second hand market for the E5-2630v3's but being new means they don't exist. :)

    Still going by new prices, an Opteron 6376 will be cheaper but roughly 33% from what I can tell. You're correct that the new Xeon's have a premium pricing on motherboards and DDR4 memory.
    Reply

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