Having looked through quite a number of DXdiags, I have a sense that there might be problems related to the Realtek on-board sound cards. Either that, or a vast majority of computers are using Realtek on-board sound.

Unfortunately I have no idea of a remedy of the problem, apart from buying a dedicated sound card, but it might be helpful for people with the right skills (and Obsidian/Bethesda) to have a look at it?

I have Realtek onboard sound....seems fine.
Try re-installing the on board sound drivers .

I have realtek onboad sound and I have no problems with sound, CTD's or freezes. Its not Realtek. Realtek Codecs work fine with Fallout New Vegas.

Current Realtek Drivers are 2.54 version (Codecs) and can be downloaded from Realtek Website.

As far as XP based systems go - the majority of the problems I see is people refuse to go the extra step and reformat and reinstall their XP. This may seem like a harsh solution, but the fact is that Fallout New Vegas does not play well with other codecs, programs running in the background. Add to this, it is also not fully quad compatible (Just like fallout 3 - .ini workaround required).

Simply put, it is not a very stable game, and is susceptible to alot of non-windows based software/codecs as well as any remnants that are not fully removed from ones system.

As a side note, I have also seen to many people trying to run Fallout New Vegas on unsupported systems and video cards or simply trying to max out their in game settings when their system can't handle it.

However, this does not excuse the many in games bugs ( Which is why I have shelved the game ) which still remain after 3 patches.

Realtek pretty much has a monopoly as far as onboard audio hardware goes, so I don't think that is an issue. I agree with Digital Justice regarding XP, many users have been running the same install for years. They've added and removed lots of crap, installed bloatware, added software that integrates with the system (like codecs), had spyware and then removed spyware, etc. A reinstall of the OS always sounds a bit harsh, but XP lacks the system file protection and UAC (as controversial as it is) of later versions so a lot of things could be overwritten

1. Yes, Realtek audio is very popular. I get the impression that some of their chips are really VERY inexpensive, which probably explains the numbers of them in circulation.

2. There are a variety of Realtek devices, and not all of them are necessarily the cheapest possible products.

3. Quite a few games are sensitive to accelerated audio settings.

4. I cannot recall immediately if Fallout 3 was sensitive in that manner, but a common suggestion in cases of uncertain origins for problems is testing with the sounds off.

Right now, Fallout: NV seems much more allergic to the combination of recent Windows OSes with recent Geforce cards / drivers, Why it should affect this game so much compared to Fallout 3 doesn't seem a logical difference, unless there's some large something we haven't been told about that was changed.

OK - I see your points. It was just that around 90% of all Dxdiags from people with problems (and not laptops - which I think may be another problem) that I have seen are with Realtek audio.

But if they are so common as you describe, that could explain that.