I was surprised – shocked! – to discover that you could buy a 1TB flash drive for less than a tenner, because I’ve been paying more than that for 16GB and 32GB versions. As mentioned in the comments below, this is almost certainly a scam, because the old computer industry adage still applies: “cheap, fast, good – choose any two”.
If your 1TB Flash drive reliably holds 1TB for a year or two, then it’s unlikely to be fast. You very helpfully ran CrystalDiskMark when I asked, and it put the read speed at 16.28MBps and the write speed at 6.52MBps. (On this benchmark, MBps means one million bytes per second.)
That’s middle-of-the-road for a USB 2.0 device, where the fastest can manage about 25MBps reading and 10MBps writing data. It’s a lot slower than your 1TB hard drive (88.80/82.08), which is somewhat slower than mine (127.7/122.6).
Speed does make a difference to usability, which is why people are moving to SSDs (~5x faster than HDDs) and M.2 drives (~25x faster than HDDs).
Obviously, it would be better to use a USB 3.0 flash drive, which can read data at 100MBps or more. Unfortunately, that would increase the cost dramatically. Even 256GB flash drives often cost in excess of £70, and can cost far more than that. You can get 3TB external hard drives – with 12 times more storage space – for similar prices.
Windows To Go
You can certainly mirror your existing 1TB hard drive to a 1TB Flash drive. However, I wouldn’t expect it to work if the hard drive failed, because all the code will still refer to the C: drive. At best, it might help you to get up and running after you replaced the failed hard drive, but so would keeping a back-up on an external hard drive. What you need is something like Windows To Go….
Microsoft has tried a few ways to exploit USB Flash drives. A decade ago, it introduced ReadyBoost, to increase PC performance. That didn’t make enough difference to catch on, but you could give it a whirl. It also offered Windows PE (Preinstallation Environment), which ran a minimal version of Windows from a USB Flash drive. Techies could use it to start a PC and install a new version of Windows Vista, or repair a PC if Windows failed to start. But WinPE has been superseded by WinRE (Windows Recovery Environment).
When Windows To Go appeared with Windows 8, Microsoft finally provided a supported way to run Windows from a USB memory stick. It was, in effect, a “Live USB” analogous to a “Live CD”. Microsoft suggested that people could carry around their own copy of Windows and use it with any available PC to safely log on to their corporate networks. This works reasonably well because they’re usually just reading stuff. If they have to save a lot of data, the slow write speed could be painful.
Unfortunately, Microsoft only released Windows To Go for the Enterprise and Education editions of Windows 10. However, people soon figured out ways to create Live USB sticks for other editions of Windows, even some old ones.
Today, there are several third-party programs that make the process easier. Rufus is probably the best known. (It is commonly used to create bootable Linux memory sticks.) Alternatives include WiNToBootic and WinToUSB Free.