For our first set of benchmarks, we are going to look at the most common suites we ran, including UnixBench (both in single and multi-threaded modes), HardInfo, sysbench, and STREAM.
One way that Intel keeps thermals manageable on the more complex Haswell-EP-based CPUs is scaling back clock rate. For example, the Xeon E5-2699 v3 operates at just 2.3 GHz, which is 300 MHz less than the -2690 v3. Single-threaded performance is still highly relevant in server workloads though, which is why Turbo Boost technology exists. A great example of this is Minecraft, which went from an obscure title to a phenomenon. The game server was bottlenecked by single-threaded performance, compelling many admins to use Xeon E3s in a quest for higher frequencies.
In our first UnixBench Whetstone/Dhrystone run, we ran the test in single-threaded mode.
Single-threaded Whetstone is relatively consistent between the three processors, despite a 700 MHz difference between the base clock rates of Intel's Xeon E5-2690 v2 and -2699 v3.
Single-threaded Dhrystone is a different story; the Xeon E5-2690 v1 pulls ahead by almost 10%. Despite the scaling of this chart, however, the results are really fairly close, even if we'd typically expect the architectural improvements rolled into Haswell to convey significant advantages over Sandy Bridge.
We can turn to the multi-threaded results to see more notable changes.
As we might expect, the threaded results illustrate that adding cores helps scale performance in workloads properly optimized for multi-core designs. The Xeon E5-2699 v3 puts up greater than 2x performance improvement versus the -2690 v1, which was top-of-the-line in its day.
We clearly see the evolution of Intel's Xeon E5-2690 line-up from its first iteration to the v3 version. The other standout is the Xeon E5-2699 v3, which shows that 18 cores and 36 threads per processor deliver huge gains in a parallelized task, particularly compared to the once-fastest Xeon E5-2690.
This is certainly less dramatic than our Whetstone and Dhrystone results, but there is still solid scaling.
Our next tests are the Fibonacci sequence calculation and FPU FFT module.
Higher core counts again benefit the v3 processors.
In all three metrics, we see linear improvements from one generation to the next, as the Xeon E5-2699 v3 pulls ahead. Intel's original Xeon E5-2690 was a 2.9 GHz part, and the -2690 v2 stepped up to 3 GHz, so the fact that lower-frequency v3s maintain a lead is telling.
Searching for prime numbers is a math problem that can be parallelized easily. As a result, it scales well with additional cores.
The Haswell-EP parts are on par with Sandy Bridge-EP and Ivy Bridge-EP when it comes to single-threaded performance. Of course, we know from the growing core counts that Intel is putting its emphasis on extra execution resources, rather than burning TDP on peak clock rates. So, maintaining the status quo there was likely deemed acceptable. But load down all available cores and it's easy to see where Haswell-EP has its greatest impact.
We did make one adjustment to the test configurations before running these tests. After noticing our control server with the Xeon E5-2699 and Supermicro-sourced boxes were scoring similarly, we decided to create a little side experiment, giving the -2699 v3 four 16 GB DDR4 DIMMS per processor. The Xeon E5-2690 v3 received eight 8 GB RDIMMs per processor to match the first-gen and v2 platforms.
The results show both the impacts of adding more memory and the nice scaling we get moving from 1600 MT/s DDR3L to 2133 MT/s DDR4. There is clearly a performance benefit attributable to the new standard; it's not just about power consumption.