Modern NVMe SSD meets vintage PCI slot in quirky experiment — M.2 drive shows storage speeds worth dying for back in the '90s

NVMe SSD installed on a PCIe to PCI adapter

(Image credit: Reddit/O_MORES)

Have you ever wondered what it would have felt like to have the leverage of today's best SSDs over three decades ago? One curious Redditor has created the ultimate storage fantasy by testing a modern M.2 PCIe 3.0 SSD on an old-school PCI slot. Yes, you read that correctly: PCI, without the "E."

The experiment may seem quirky at first, but it actually offers a fascinating look into how far technology has evolved. On one side, you have the PCI slot introduced in 1992; on the other, the NVMe storage specification released in 2011. While the Redditor didn't provide the SSD specifications, the screenshot shows the drive labeled "Gen3NVMe," so we can reasonably assume it's a PCIe 3.0 drive. The first PCIe 3.0 drives entered the market around 2013, so we're looking at around a 20-year technological gap.

The setup is simple. The Redditor installed the M.2 PCIe 3.0 SSD into a standard M.2-to-PCIe AIC (Add-in Card), the same type typically used to run an M.2 SSD in a PCIe expansion slot. Consequently, the user inserted the AIC into the PCIe-to-PCI adapter, which ultimately plugs into the PCI slot on the motherboard. PCIe and PCI are physically and electrically different because they have different pinouts. However, they're logically compatible, so it's possible to use PCIe on PCI without special drivers or anything of the sort. The PCIe-to-PCI adapter used in this project is kind of like a Rosetta Stone, so to speak.

Teaching my NVMe drive what life was like in the '90s by forcing it to run on the PCI bus from r/pcmasterrace

The results from the user's CrystalDiskMark run show sequential read and write speeds of 208 MB/s and 58 MB/s, respectively. They seem underwhelming, given that PCIe 3.0 SSDs typically peak at around 3,500 MB/s. However, we have to consider that the performance isn't bad, given the severe bandwidth at play. If you look at it superficially, the Redditor is essentially bottlenecking the M.2 interface by feeding it fewer lanes.

A standard 32-bit PCI slot running at 33 MHz has a maximum theoretical bandwidth of just 133 MB/s. However, some designs achieve 266 MB/s bandwidth with a 32-bit configuration at 66 MHz. Meanwhile, the 64-bit interface, prevalent on enterprise or server motherboards, can offer either 266 MB/s (64-bit at 33 MHz) or 533 MB/s (64-bit at 66 MHz). The Redditor confirmed his PCI slot was running at 66 MHz, so the system likely had a consumer motherboard. It also explains why the PCIe 3.0 SSD surpassed the 200 MB/s mark in the benchmarks.

Despite the bandwidth bottleneck, 200 MB/s is still respectable and would probably be considered remarkable in an era when hard drives communicate over an IDE or SATA interface. The experiment could be a valid method for retro computing enthusiasts to breathe new life into legacy hardware. Then again, there's the fun aspect: a certain inexplicable satisfaction when you can get hardware from different eras to play nicely together.

Follow Tom's Hardware on Google News, or add us as a preferred source, to get our latest news, analysis, & reviews in your feeds.

Zhiye Liu is a news editor, memory reviewer, and SSD tester at Tom’s Hardware. Although he loves everything that’s hardware, he has a soft spot for CPUs, GPUs, and RAM.