Make sure your video drivers are DX8 certified. Some are, and some are not.
But as a general rule, it is not a good idea to grab the first release of anything from Microsoft.
To my knowledge, DX8 will not buy you anything until the games acutally make use of the DX8 additions. In light of that, I would just stick to DX7 as it is solid and stable and wait for a couple more months before committing to something that is really not useful yet.
Of course, I am pretty conservative about upgrades. I ask myself, "Is there any benefit to this?" If the the answer is "No", then I don't upgrade. For DX8, I cannot find a compelling reason to upgrade as there are no games that support the new features of DX8.
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Roy "Skuzzy" Neese
President, AppLink Corp.
http://www.applink.netskuzzy@applink.net