Although recent PCs use increasingly fast storage devices in the form of modern NVMe SSDs, gamers still spend quite a bit of time looking at loading screens. One of the reasons is that today’s game levels are loading steadily increasing amounts of data.
However, compared to switching from a hard drive to any SSD – which will easily cut loading times in half – the difference between SSDs is not nearly as apparent.
NVMe/PCIe Gen3 Vs. Gen4
As of 2021, the fastest SSDs on the market utilize the NVMe (Non-Volatile Memory Express) protocol and the PCI Express 4.0 (Gen4) interface.
The maximum transfer rate of these drives over the standard four PCIe 4.0 lanes is well above 7,000 MB/s, which is twice the bandwidth compared to Gen3. This means that market leaders such as the Seagate FireCuda 530 and WD Black SN850 are already performing near the upper limit – at least in synthetic benchmarks.
In games and many other practical scenarios, on the other hand, the situation is quite different.
As seen in this test (by GamingPCBuilder), any of the SSDs will effectively cut the loading times by between a half and two thirds in FF XIV, which is not surprising. What is perhaps less expected is that the high-end WD Black SN850 is only less than half a second faster than the entry-level Gen3 WD Blue SN550.
For perspective, the SN850 is a significantly more expensive drive that offers sequential transfer rates of up to 7,000 MB/s and 1,000,000 IOPS. The SN550 is a DRAMless budget model offering up to 2,400 MB/s sequential read speed and 410K IOPS.
What this seems to show is that an entry-level SSD may, at least in some cases, offer real-world performance that is only marginally behind the fastest models on the market. At least for now.
DirectStorage Set to Take Better Advantage of NVMe
One of the key reasons for the slower than expected loading times is that today’s theoretically ultra-fast SSDs are bottlenecked by the process of getting data into VRAM, i.e., the graphics card’s memory.
In the current situation, compressed data from the SSD has to be loaded into RAM and decompressed by the CPU before making its way to the GPU. This issue will be alleviated by Microsoft’s DirectStorage technology in Windows 11, which essentially removes the need for CPU decompression. As a result, you will get a lot more performance out of your PCIe Gen3 – or better yet Gen4 – NVMe SSD.
But until DirectStorage – and potential other, similar technologies, are ready for prime time – and are also fully utilized by developers – the difference between Gen3 and Gen4 SSDs will continue to be fairly minor in the real world. Even a decent SATA SSD is not very far behind its much more modern M.2 NVMe counterparts in many real-world scenarios like loading game levels.