For Windows power users, system administrators, and homelab tinkerers nursing older desktop or server platforms, this practical upgrade path raises an interesting question: why spend hundreds of dollars replacing a working CPU, motherboard, and DDR3 memory kit when an unused PCIe slot can deliver four-lane NVMe bandwidth for the price of a takeout lunch? Before you rush to grab the nearest adapter card, however, there are critical hardware, firmware, and electrical caveats that separate a smooth storage upgrade from a frustrating return label.
Giving Haswell-Era Silicon a Modern Storage Lane
The machine at the center of MakeUseOf's build is a classic piece of "if it isn't broken, don't fix it" hardware: an Intel Xeon E3-1225 v3 processor sitting in a Gigabyte LGA1150 motherboard, originally configured with two 2.5-inch SATA SSDs and an aging mechanical hard drive. Built around Intel's Haswell architecture from the mid-2010s, boards from this era largely predated ubiquitous onboard M.2 sockets. Worse yet, the server's chassis could only physically house three 2.5-inch drives, meaning every standard drive bay was already full.
Rather than gutting the working server to accommodate a single 512 GB Gigabyte NVMe drive left over from a canceled USB-C portable enclosure project, Gibson picked up an MHQJRH Dual M.2 PCIe Adapter for just over $17. Because NVMe is natively based on the PCI Express bus, a passive PCIe-to-M.2 adapter does not need an expensive bridge chip to translate protocols for an NVMe drive; it simply routes the motherboard's PCIe lanes directly to the M.2 M-key connector.
Still, buying budget adapter cards requires reading the fine print carefully. While the MHQJRH card features two M.2 slots on a single PCB, those two sockets are not interchangeable:
- Socket 1 (NVMe): Uses an M-key connector wired directly to the motherboard slot via PCIe 3.0 x4.
- Socket 2 (SATA M.2): Uses a B-key connector limited to 6 Gbps SATA speeds and requires running an included 7-pin SATA data cable from the adapter card to an open SATA port on the motherboard.
If you buy a dual-slot adapter assuming you can drop two PCIe NVMe sticks into a single x4 card, you will be disappointed. Multi-drive NVMe cards either require a motherboard that supports PCIe lane bifurcation in a wider x8 or x16 slot, or an onboard PCIe packet switch chip that costs significantly more than $17. For a single spare NVMe SSD, however, the primary PCIe 3.0 x4 socket on the budget card was all the server needed.
Section Summary:
- Older LGA1150 motherboards typically lack onboard M.2 slots, but NVMe drives communicate natively over PCI Express.
- Inexpensive dual-M.2 PCIe adapters often split their functionality, offering only one PCIe NVMe slot alongside one cable-dependent M.2 SATA slot.
From Raw Block Device to Windows 11 Virtual Machine Storage
Putting the physical card into the top PCIe slot above an existing PCI network interface card was only half the battle. Once the server powered up, the Linux-based Proxmox Virtual Environment hypervisor immediately detected the hardware without needing extra drivers, registering the 512 GB Gigabyte drive as /dev/nvme0n1 with a reported binary capacity of 476.9 GiB (the standard difference between decimal gigabytes used by drive manufacturers and binary gibibytes used by operating systems).
For anyone performing a similar upgrade on Proxmox or a Linux host, verifying how the operating system sees the new bus and block devices takes a single terminal command:
lsblk -d -o NAME,MODEL,SIZE,TRAN
That TRAN (transport) column is particularly handy when managing mixed-storage servers, as it cleanly separates nvme devices from legacy sata drives before you start formatting disks.
To turn the raw /dev/nvme0n1 block device into usable hypervisor storage, the drive was initialized through the Proxmox web interface as an LVM-thin storage pool named vm-nvme, which showed 501.74 GB of active capacity in the Proxmox summary view. In Proxmox environments, LVM-thin allocates blocks dynamically as data is written rather than claiming the entire volume up front, which allows thin provisioning and efficient snapshots for virtual machine disks.
Migrating the existing Windows 11 virtual machine onto the new solid-state tier required zero reinstallation:
- Shut down the Windows 11 virtual machine cleanly.
- Select the VM's hardware tab in Proxmox and choose the Move Storage tool for the 64 GB system disk.
- Set the destination to the newly created
vm-nvmeLVM-thin pool while leaving the option checked to keep the original virtual disk on the Intel SATA SSD as a fallback. - Boot the Windows 11 VM from the new NVMe pool, verify that the installation starts cleanly and remains intact, and then delete the leftover SATA copy.
Section Summary:
- Modern hypervisors like Proxmox recognize PCIe-mounted NVMe drives immediately as
/dev/nvme0n1. - Using Proxmox's built-in Move Storage utility allows administrators to migrate an intact Windows 11 virtual disk from SATA to an LVM-thin NVMe pool with minimal downtime and an easy rollback path.
Measuring the Gains: SATA vs. NVMe Inside a Windows 11 VM
When system RAM is tight on an older virtualization host, fast storage is not just a luxury—it is the safety net that keeps guest operating systems responsive during heavy boot sequences, paging, and background updates. After moving the 64 GB system disk, the Windows 11 VM felt noticeably snappier booting to the desktop, though subjective impressions without a stopwatch only tell part of the story.
To quantify the change, MakeUseOf ran CrystalDiskMark inside the Windows 11 guest before and after the storage migration. Both test passes kept the exact same virtual hardware envelope—two vCPU cores, 8 GB of RAM, and the Proxmox VirtIO SCSI controller—running three passes with a 4 GiB test file size.
| CrystalDiskMark Test (3 Runs, 4 GiB) | Intel SATA SSD (Read / Write) | Gigabyte NVMe SSD (Read / Write) | Measured Improvement |
|---|---|---|---|
| Sequential Q8T1 | 454 MB/s / 150 MB/s | 1,896 MB/s / 1,846 MB/s | ~4.2x faster reads / ~12.3x faster writes |
| Random 4K Q1T1 | 8.27 MB/s / 39.82 MB/s | 21.70 MB/s / 51.34 MB/s | ~2.6x faster reads / ~29% faster writes |
The numbers illustrate why even a PCIe 3.0 NVMe drive runs circles around the legacy SATA III interface. Sequential read throughput jumped roughly 4.2 times higher (from 454 MB/s to 1,896 MB/s), while sequential writes surged past the old SATA ceiling from 150 MB/s to 1,846 MB/s. More importantly for everyday Windows 11 responsiveness, single-queue, single-thread Random 4K reads more than doubled from 8.27 MB/s to 21.70 MB/s, and Random 4K writes climbed by about 29% to 51.34 MB/s.
A bit of veteran benchmark perspective is warranted here. As Crystal Dew World notes in the official CrystalDiskMark documentation, disk benchmark results depend heavily on test file size, controller virtualization overhead, fragmentation, and CPU speed—and in CrystalDiskMark, MB/s explicitly represents decimal megabytes (1,000,000 bytes per second). Because these figures were captured inside a virtualized Windows 11 guest running over VirtIO SCSI with two Haswell vCPU cores, they reflect the real-world throughput delivered to the guest OS in this specific setup rather than the theoretical bare-metal peak of the drive. Even through a virtualization layer on ten-year-old silicon, breaking free of the 6 Gbps SATA bus removed a massive I/O bottleneck.
Section Summary:
- Sequential read speeds inside the Windows 11 VM increased 4.2x, while sequential writes jumped more than twelvefold.
- Random 4K performance—the metric most responsible for OS boot and application responsiveness—saw more than double the read speed and a 29% boost in single-threaded writes.
The Crucial Caveats: Slot Wiring and the BIOS Boot Trap
Before you dust off an old desktop PC or server and order a PCIe-to-M.2 adapter, you need to verify two hardware realities that routinely trip up upgrades on vintage boards: PCIe slot electrical specifications and UEFI boot support.
First, physical slot size does not guarantee electrical speed. On the Gigabyte LGA1150 motherboard used in MakeUseOf's server, only the top expansion slot provided a full PCIe 3.0 x4 connection. A second slot lower on the board could physically accept the adapter card, but its electrical wiring was limited to PCIe 2.0 x4—which would have cut maximum theoretical bandwidth in half. On many older consumer and workstation motherboards, secondary PCIe slots share lanes with chipset SATA ports or drop down to x1 or PCIe 2.0 speeds. Checking the motherboard manual before choosing a slot is mandatory if you want the adapter to negotiate full PCIe 3.0 x4 link speeds.
Second, and most importantly for Windows users: operating system storage support is not the same thing as motherboard boot support.
In this server upgrade, Proxmox itself continued to boot from its existing SATA SSD, while the NVMe drive acted strictly as a secondary storage pool for virtual machines. Once the Linux kernel (or a modern Windows 10/11 kernel) is already running, its built-in NVMe driver can easily talk to a drive on a PCIe adapter. However, if you try to install Windows directly onto a PCIe-adapted NVMe drive and use it as your primary boot drive on a decade-old PC, you may hit a brick wall.
Why? Unlike older SAS or SATA RAID controller cards that carried their own onboard Option ROMs to initialize drives during startup, standard M.2 NVMe SSDs and passive PCIe adapters do not include legacy boot ROMs. For a motherboard to boot directly from an NVMe drive, its UEFI firmware must explicitly contain an NVMe DXE driver module. Many boards prior to Intel's 9-series and 100-series chipsets lack native NVMe boot support in their stock BIOS/UEFI. While enthusiasts sometimes work around this by keeping a bootloader like Clover on a SATA drive or USB stick —or by doing precisely what Gibson did and booting a hypervisor or host OS from SATA while placing heavy workloads and VM disks on the NVMe volume—you should never assume an older motherboard can boot directly from a PCIe M.2 adapter without checking its firmware capabilities first.
When Does the $17 Upgrade Make Sense?
Is a PCIe-to-M.2 adapter the ultimate cure for aging PC hardware? If you already have an NVMe SSD sitting in a drawer—left over from a laptop upgrade or an abandoned enclosure build—and an open PCIe 3.0 x4 (or better) slot on your motherboard, spending $15 to $20 on an adapter card is one of the highest-return upgrades in PC computing. Even if you have to buy a budget NVMe SSD alongside the adapter, the combined price often rivals a comparable 2.5-inch SATA SSD while delivering several times the sequential and random throughput, plus saving you from routing SATA power and data cables inside a cramped case.
By pairing a existing SATA boot drive with a PCIe-mounted NVMe pool, you get all the reliability of legacy firmware boot paths alongside modern solid-state speed where your virtual machines, games, or scratch disks actually feel it. Sometimes, teaching an old motherboard a new trick really only takes seventeen bucks and a spare expansion slot.
Section Summary:
- Always verify your motherboard manual to ensure the target expansion slot supports PCIe 3.0 x4 electrically, not just physically.
- Older motherboards often cannot boot directly from NVMe drives due to missing UEFI firmware drivers, making PCIe NVMe adapters ideal as secondary high-speed storage or VM pools alongside a SATA boot drive.