I read up extensively before buying this card. I read that people trying to use it with Vista have problems. This is mainly due to how Vista handles DirectSound, which makes it necessary to use an additional application called Creative ALchemy if you want to use EAX effects. The Vista problem is not specific to this sound card though, of course.
Anyway, as I am using good old XP I thought I would be OK. However, I immediately experienced an intermittent, but very severe crackling sound. Sometimes I even lost sound completely and had to reboot and a few times the PC actually crashed. After Googling this, I found on Wikipedia and Creative's own forums that this is a long known problem. It appears to be a problem with the PCI bus on mobos with certain chipsets. Creative is convinced that it only affects nVidia nForce chipsets, as these are the mobos with which they have run tests. However, I and others with VIA chipsets have experienced the same problem. It looks as though X-Fi cards really need to be used with the PCI Express interface, but the Xtreme Gamer is only available as PCI. As I only have standard PCI slots, I took my X-Fi back to the store and bought myself a second hand Audigy 2 ZS (superior to the SE version) from eBay and that works with no problems! The X-Fi is a great card IF you can get it to work properly.