Benchmarking data storage or transfer speeds can seem straightforward, at least in theory. Assemble a group of test files on your PC; store, copy, upload or download them, and measure how long this all takes. Easy, right?

Well, not necessarily. Compression could be an issue. You might measure how long it takes to save a bunch of files to an SSD, for instance, but if the drive uses compression – as many do – then the speed you see will vary according to your test data.

NonCompressibleFiles is a simple portable tool which offers a quick solution. Enter the number of files you’d like, their individual size, click Start, and that’s it: the program immediately creates a set of test files which can’t be compressed.

Everything is controlled from one straightforward dialog box

Does it work? Our tests suggested yes – if anything, it’s a little too good. When we put our generated files through 7Zip, they were 1.29% larger than the originals. And so we could use any of these in a data storage or transfer test and be very sure that compression wasn’t going to have any significant effect on the results.

Of course, real world data can often be very compressible, so there might be a case for running a second benchmark with, say, text files, and comparing the results.

Alternatively, NonCompressibleFiles is able to produce files with the maximum possible compression. This also delivered, with 7Zip reducing our 1GB of test files to a mere 152KB. Run benchmarks with both file types and you’ll see exactly how much difference compression can make to your measured operation, which could be an interesting test in itself.

NonCompressibleFiles isn’t a program you’ll need every day, then, but if you regularly evaluate hardware or software then it might be occasionally helpful, and it’s certainly worth adding to your testing toolkit.