I'm currently downloading the civ5 demo through steam. I ordered a DVD copy, which will probably arrive next week.

I do not have a DVD drive installed on my PC though. Will I be able to upgrade the demo installation to the full version using the key I get with my DVD copy? Or will I have to download everything a second time?

  • 1
    May I ask why you bought a DVD copy knowing you don't have a DVD-ROM?
    – Drew
    Commented Sep 23, 2010 at 10:21
  • A lot cheaper, i knew the key would be compatible with steam, and it's only a specific pc that doesn't have a dvd-drive.
    – Bubblewrap
    Commented Sep 23, 2010 at 15:37

4 Answers 4


I played the demo on Steam (4gb download) and then purchased the game on Steam (another 4gb download). It seems silly but this is the way they have it set up.

  • See the comments to my reply, Raven tells a different tale...
    – badp
    Commented Sep 25, 2010 at 22:53
  • 1
    Just tried it as well, and can confirm this answer. Raven is right in that it replaces the Demo entry from the steam games list. It does not reuse its files though, it's still a 4gb download.
    – Bubblewrap
    Commented Sep 27, 2010 at 17:53

If a Steam demo shares files with the full game, you will have both the demo and the full game in your store page; the latter will be marked as preloaded and doubleclicking on it brings you to the purchase link. When you actually complete the purchase, only additional full-game-only files are downloaded.

If that is not the case, you may have to redownload the whole shebang.

  • Would the purchase link also give an option to enter a key, rather than buying through steam?
    – Bubblewrap
    Commented Sep 22, 2010 at 13:48
  • @Bubble, I guess purchasing via steam and unlocking via key doesn't make much of a difference here. That's assuming Steam does accept Civ5 keys, however.
    – badp
    Commented Sep 22, 2010 at 13:56
  • It sounds like Civ 5 DVD keys are in fact Steam Keys, which is lucky for you, Bubblewrap. In my experience, some demos will save you some download time, and some will not-- it depends on how those files are marked on Steam's servers and how much is shared between the demo and full game. I've seen Steam games completely install from fresh separate from the demo, and I've seen games use some of the demo's install.
    – WorldMaker
    Commented Sep 22, 2010 at 23:59
  • 4
    I bought Civ V through steam after downloading the demo. When I went to install Civ V, it said something along the lines of "synchornizing" and when the game was installed, the demo was removed. So if nothing else, I can confirm that the demo is replaced, not ignored. Commented Sep 25, 2010 at 22:33
  • I just wanted to confirm this still works, 8 years later. I bought "The evil within" after downloading the 9GB(!) Demo. When you install the game after purchase, it will allocate disk space. I opened Windows Explorer to see what happens. Steam changed the "The Evil Within Demo" folder to "The Evil Within" and then started the download the remaining 31GB, meaning the 9GB demo were already accepted.
    – marts
    Commented Aug 11, 2018 at 10:32

From the official steamworks FAQ on 2k's Civ V forums:

Q. How will Steam know that I bought a boxed copy of the game?

A. The box contains a product code that you use to register your purchase to your Steam account. The box also contains a disc that contains the data files for the entire game. When you install from this disc, it will install Steam if necessary and then place all of the game files on to your hard drive, negating the need to download the game from the Internet.

So even though you don't have a DVD drive, you shouldn't have a problem installing Civ V, as as soon as you register via steam, you can simply download the game through steam.


  • Uhm, i dont see how this answers the question...your comment to badp's answer was much more useful, even though it's being contradicted by antoher answer. I already knew i'd be able to download the game completely through steam even if i buy the DVD.
    – Bubblewrap
    Commented Sep 26, 2010 at 9:25
  • Ah, seems I misread the question. Commented Sep 26, 2010 at 13:37

I'm downloading the demo for Civilization V now. It seems like Steam has to download some stuff, but not 4 GBs worth; more like 1 GB. So my guess is it uses the files you've already got, but needs to download the unused content, probably Multiplayer and all the other maps.

Don't forget you can play other Steam games while downloading. Just alt+tab out and pause and resume download, then alt+tab back to your game.

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