Here we’ll be focusing on the i7-8750H with single-channel memory, and how that differs from the dual-channel results. Later we’ll discuss gaming, as lower memory bandwidth has an impact there as well.
Whether memory bandwidth has an effect on performance depends on the application. In Cinebench, x264 encoding, Handbrake and Excel, there is a marginal difference between the Aero 15X and what we previously established was the best case performance for the Core i7-8750H. This isn’t that surprising: encoding and rendering tests largely don’t require high bandwidth, and neither do Excel calculations.
Decompression also seems largely unaffected with just a 1 percent performance difference in 7-Zip, though compression is hit fairly hard, dropping by 20 and 23 percent respectively in our 7-Zip and WinRAR benchmarks. That’s a pretty significant difference for just increasing memory bandwidth, so if you have workloads that are compression heavy, you’ll benefit the most from adding in that second RAM stick.
Adobe apps also like additional memory bandwidth. Premiere encodes are 10 percent slower, and Photoshop filters like the Iris Blur are 16 slower with just one stick of RAM. That’s a considerable difference in Premiere in particular, where you might be waiting a while for an encode to complete. MATLAB is well known to suffer with low memory bandwidth, falling behind by 19 percent.
Across the PCMark suites, including PCMark 10 and PCMark 8, the Aero 15X was slower than our best-case i7-8750H results by 2 to 5 percent. Considering the multi-workload nature of PCMark, this is a fair result, as some tests are not affected and others can be hit a bit harder.
On average across all our productivity workloads, the single-channel Aero 15X is 5 percent slower than our dual-channel Core i7-8750H configuration. Essentially, that’s the performance you’re missing out on by not having that second stick of RAM inside the Aero 15X, which is why most companies opt for dual-channel out of the box. It’s also the data you’ll need when tossing up between a range of i7-8750H laptops; if you can find one that’s dual channel out of the box, you can expect 6 percent more performance than the Aero.
Of course it’s also worth comparing the new i7-8750H Aero 15X to the older one with the i7-7700HQ inside. The original Aero also uses single-channel memory, and in workloads that are not affected by the GPU - as our two Aero 15 review systems had different GPUs inside - we’re seeing significant gains. In multi-threaded tests like Cinebench and video encoding, performance is typically 35 to 55 percent faster with the new six-core CPU. That’s a massive performance jump and definitely gives you a reason to upgrade, even if you’re rocking a system from just one generation ago. If you’re moving from an i7-7700HQ laptop with dual-channel memory, performance gains are lower on average, though again a number of typical productivity workloads are unaffected by memory bandwidth.
