Dell XPS 15 (9550) Review: Pushing The Infinity Edge (Updated)

XPS 15 SiSoft SANDRA, ATTO And SunSpider Benchmarks

Our Test Methodology And Comparison Data:

Before we dive into the benchmark numbers that follow, we should underscore our approach to testing and reference comparison data. The Dell XPS 15 presents a bit of a dilemma when it comes to what a machines in its weight class it should be compared to. This notebook is essentially a 4 pound thin and light machine, with specs that are more in line with notebooks of a beefier weight class. As such, to show a balanced view of performance relative to other notebooks on the market, on the pages that follow we compare the XPS 15 to both light, under 4 pound ultrabooks and also larger premium notebooks. We even threw a few gaming notebooks into the mix. Remember, comparing one notebook config to another is also never an exact science. Machines are often configured with different memory configs, different storage components and so on. However, the data that follows will give you a good visual of how the new Dell XPS 15 performs in a variety of use cases.

First, we ran SiSoftware's SANDRA, the System ANalyzer, Diagnostic and Reporting Assistant. The benchmarks we chose are four major tests, including CPU Arithmetic, CPU Multimedia, Memory Bandwidth, and the Physical Disk test.

Synthetic Benchmarks

SiSoft SANDRA has a variety of tests that stress specific components or simulate certain tasks. SANDRA receives frequent updates, so if you use the benchmark, check to make sure you have the latest version. The scores below are represented versus other machines in the SiSoft SANDRA database.

CPU And Multimedia Tests
SANDRA Memory SANDRA Storage
Memory Bandwidth And Physical Disk Test

This quick sanity check with SANDRA doesn't show any surprises and the quad-core Skylake CPU puts up impressive numbers, especially for a notebook chip. What is also impressive however, are the memory bandwidth and storage numbers here. A notebook platform pushing 24GB/sec of memory bandwidth is pretty fantastic, as is a notebook platform that offers over 2GB/sec of read bandwidth for its storage subsystem.

We decided to delve a little further into the storage performance profile of the new XPS 15, so we fired up ATTO as well.

ATTO Disk Benchmark

While it's still pretty delightful to see a notebook drive pushing over 1.7GB/sec for reads and over 500GB/sec for writes, we've seen the Samsung PM951 PCI Express NVMs SSD, that's configured in the XPS 15, push a bit more bandwidth than this, hitting in excess of 2GB/sec as our SANDRA tests showed. We reached out to Dell on this and its apparent that there maybe some driver optimization still going on. Different versions of the NVMe driver for Windows 10, whether it be Microsoft's default driver or the drive manufacturer's, offer different performance. Dell is currently employing Microsoft's driver here and could squeak out more performance if they moved to Samsung's.

SunSpider Javascript Benchmark
Javascript Processing Performance

Next up, we have some numbers from the SunSpider JavaScript benchmark. According to the SunSpider website:

This benchmark tests the core JavaScript language only, not the DOM or other browser APIs. It is designed to compare different versions of the same browser, and different browsers to each other. Unlike many widely available JavaScript benchmarks, this test is real-world, balanced and statistically sound.  

We should note that this is more of a platform test, in that different browser versions, associated with different OS types can and do affect scores.

Here we're comparing the new Dell XPS 15 to a number of very light ultrabook-class machines or in some cases hybrid 2-in-1 devices. The XPS 15 shows very strong here with the best ultralight notebook score we've ever recorded, likely due to some of the recent advances in Intel's 6th gen Skylake processor family and its Speed Shift technology in conjunction with the latest build if Windows 10 and the Microsoft Edge browser, all of which add up to a smoother, more responsive user experience.

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