Vestin: It doesn't. I just checked and I get a stable >700 kB/s download speed via browser, so the problem IS probably somewhere nearer your end...
It's true, though. Huge sales like this can probably tax their servers, especially when they first begin, but GOG's speeds can be pretty inconsistent. Though I've never had speeds faster than about 350-450kB/s, I'm usually nowhere near that level most of the time I download here.
That's another reason to keep your games backed up. GOG could do with some speed improvements (and not too long ago there was a thread that served as the first step toward that goal), they deserve a good amount of the blame, but you also have the opportunity to avoid much of that waiting by taking matters into your own hands and preventing the need to download your content from their servers a second time ("second time" not counting the occasional file corruption, a legitimate concern for people with limited bandwidth, but once you have a perfect download you ideally never have to do it again).
As for those four hard drives, why on earth would you need to format four drives? O_O
It's good practice to reserve one hard drive, or even just a partition of that drive, for system files. Registries get screwed, folders are made, and you have no idea what's taking up space one day. This is the drive that gets the most access and will probably fail the soonest because of it. A secondary drive can be used to store files. Your system doesn't normally read from it, and even if it has infected files, it's essentially quarantined from the new system install on your main drive, since it hasn't been "configured" to run any sort of undesirable background processes.
With a storage drive, you set up the folder hierarchy, so you always know what should and shouldn't be there (i.e. there shouldn't be registry files or the usual system folders, and if they show up on the storage drive, they don't belong there and should be deleted). WinDirStat is a useful program for seeing what's taking up space, by the way, but good organization on a storage drive should reduce the need for that. I have everything important on my second drive. Wallpapers, drivers, saved game data, installers for my favorite programs, I can format my main drive on a whim and restore things as they were (or better) in no time flat.
Not a lot of good it does to say now, but formatting all your drives like that was
probably not necessary. I've had a lot of friends who have done that too. You have so many drives that you barely need to even worry about partitioning, but it can be good to learn about anyway. Just know that you can wipe your OS, and only your OS, and that will solve all of your problems. There's no need for any more brute force than that, unless you've kept an unorganized system and just want to kill everything.