My 6-year-old PC is slightly below the specs for Myst (1.4 GHz, whereas 1.8 is listed as the requirements). I don't really feel like upgrading my computer (I mostly play on consoles, and I've got more than enough performance for MS Office / Web browsing).
So, will this run on my oldie? Anyone playing this game on low-spec PCs?

Specs can usually be fudged with a little, but your CPU speed is a pretty essential benchmark. Your CPU needs to spin at 18000000000 cycles per second, but yours will only make 14000000000 cycles per second. Looked at like that, the difference is rather sizable.
New CPUs can be bought for relatively cheap, and improve your computer in many ways than simply gaming. In this case I'd recommend a new midline CPU.

Myst isn't really system intensive at all, you could probably run it on a toaster.

Well, never CPU's with similar Ghz's tend to be more powerful than older ones. And Myst is from... 1993? And Riven from 1997, correct? How can it actually require 1.8Ghz? Were those even around back then... :) I ran Myst on 386, I seem to recall... Or was it a C=64... Could have been 486 80Mhz. Though, I do need to read on how GoG actually run these, is it a form of emulation, thus needing a bit more...
Noting the first bit, my Atom 1.6 Ghz powered netbook runs Riven wonderfully.

I'm running Myst and Riven in a SU7300 processor (1.3 GHz, dual core). The only heavy requirements these games have are the video software, which is way less heavy on your machine than Youtube.
The first time I played these games was on a Macintosh (yeah, Macintosh, no MacOS) with a 3.5" floppy drive. Don't worry, your computer will be up to the task.

Thanks for the tips, guys. I put my $5 at stake and bought the game :-)
Looks like the Hardware requirements were (way) overstated - the game runs just fine. Yeah, the visuals are kinda crappy (looks like 256 colours?), but I was expecting this.
I knew the game is old and had barely any requirements at all - I just thought running it from DosBOX boosted the reqs like that.
Oh, and I have a 1.4 GHz with 1GB RAM and some old-school ATI Radeon (9500?).