Buying an external drive often comes down to two overlooked details: the port you plug it into and the file system it ships with. These explain why a supposedly fast drive copies slowly or why a 6 GB movie won’t fit on an empty USB stick. TechNews DevTop breaks down the real-world performance of external SSDs, mechanical hard drives, and USB flash drives, and explains how to format them for seamless use on both Windows and Mac.
- Speed hierarchy: External SSDs offer the highest sustained speeds, followed by USB flash drives, with mechanical hard drives trailing due to their spinning platters and moving heads.
- Bottleneck reality: The slowest link in the chain—port, cable, or drive—dictates actual transfer speeds, not the drive’s advertised maximum.
- Format for compatibility: exFAT is the only file system that provides full read/write support on both Windows and Mac without the 4 GiB file size limit of FAT32.
SSD, HDD, or USB Stick: What’s the Real Difference?
The practical difference is sustained speed. An entry-level USB 3.0 flash drive like the SanDisk Ultra advertises up to 130 MB/s sequential read, while a portable SSD like the Samsung T7 claims up to 1,050 MB/s read and 1,000 MB/s write. These are manufacturer figures under ideal conditions, but the order of magnitude is real: roughly eight times faster reads.
External mechanical hard drives play a different game. They rely on a spinning platter and a moving head, so they can’t compete with SSDs on speed. Their strength is capacity, which is why they still make sense for storing terabytes of photos or backups you don’t access daily. Before buying, compare the price per terabyte with that of an SSD of the same capacity.
My rule of thumb is simple: a USB stick for transporting files, a hard drive for archiving, and an external SSD for working with what’s inside (video editing, moving photo libraries, running games). If you’re concerned about how long each technology lasts before failing, that’s covered in detail elsewhere on TechNews DevTop.
Why Your Fast Drive Copies Slowly: The Connector Rules
Because the chain runs at the speed of its slowest link: the computer’s port, the cable, and the drive itself. Samsung spells this out in the T7’s spec sheet: to reach those 1,050 MB/s, the host and cables must support USB 3.2 Gen 2 (10 Gbps) and UASP mode must be enabled. Plugged into an older port, the same SSD performs only as fast as that port allows.
To make sense of the labels, the USB Implementers Forum (USB-IF) uses logos that indicate speed directly in gigabits per second: USB 5Gbps, 10Gbps, 20Gbps, 40Gbps, and 80Gbps. Watch the units: these are gigabits, not gigabytes. Divide by eight to get the theoretical ceiling in megabytes: 10 Gbps equals 1,250 MB/s, so a 1,050 MB/s SSD is already near that port’s limit, while 5 Gbps caps out at 625 MB/s. The rest is lost to protocol overhead and the drive itself.
The physical connector guarantees nothing: a USB-C port can run at any of those speeds, or at USB 2.0. How to tell by the cable and port is explained in our guide to USB-C speeds, charging, and video.
exFAT, NTFS, APFS, or FAT32: Which Format Should You Choose?
If the drive must be read and written on both Windows and Mac, choose exFAT. It’s the only one of the four that appears both among the formats supported by Windows’ format command (FAT, FAT32, NTFS, exFAT, ReFS, and UDF) and among those in Mac’s Disk Utility (APFS, MS-DOS FAT, and ExFAT), and it doesn’t carry FAT32’s per-file size limit.
That limit is the source of the classic “not enough space” error on a half-empty USB stick. According to Microsoft’s file system comparison table, FAT32 does not support files larger than 4 GiB, while exFAT and NTFS reach 2^64–1 bytes—a limit you’ll never hit in practice. A high-quality movie or a disk image can easily exceed 4 GiB.
What about the others?
- NTFS is Windows’ native format. It offers permissions, encryption, compression, and a metadata journal that exFAT lacks, per the same Microsoft table. Choose it if the drive will only ever connect to a PC.
- APFS has been the default on Macs since macOS 10.13. Apple describes it as optimized for flash storage and SSDs, though it also works on hard drives. Use it if the drive will only be used with a Mac; it includes an encrypted variant.
- FAT32 (called MS-DOS FAT on Mac) only makes sense for older devices that don’t support other formats; if in doubt, check the device manual. Apple recommends it for volumes up to 32 GB and exFAT above that capacity.
One exFAT caveat worth knowing: because it lacks a journal, it’s more fragile if you disconnect the drive mid-write. Ejecting before pulling the cable isn’t fussiness—it’s how you avoid corruption.
How to Format the Drive for Both Systems
Formatting erases everything on the drive, so first copy anything you want to keep.
On a Mac, the steps from Apple’s guide to formatting a disk for Windows are:
- Open Disk Utility and choose View > Show All Devices.
- Select the disk in the sidebar (the device, not just the volume).
- Click Erase and, in the Scheme menu, choose the partition scheme.
- In Format, choose ExFAT if the drive is larger than 32 GB, or MS-DOS (FAT) if it’s 32 GB or less.
- Give it a name of no more than 11 characters and confirm.
On Windows, the most direct and documented route is the command line. With the drive on letter E:, for example, the command format E: /FS:exFAT /V:DATA /Q applies exFAT, labels it DATA, and performs a quick format. Before pressing Enter, double-check the letter: format doesn’t ask what’s on the drive.
If the drive will hold important backups, formatting is the easy part. The hard part is not relying on a single copy on a single disk—that’s where the 3-2-1 rule comes in, explained in our guide to NAS vs. cloud storage.
The most useful takeaway is to stop looking only at capacity. A 1,000 MB/s SSD plugged into a 5 Gbps port with a random charging cable is money wasted, and a USB stick formatted in FAT32 is a trap for anyone moving video. Before buying, check which port you have; before filling the drive, check which format it uses. Those two minutes save hours of slow copies and errors that look like failures but aren’t.