That's like me asking why on earth would somebody buy a million dollar car (some people do). Well, cause they are able to do it.
There is a big difference between your 7900GTX and a "million" dollar car. Your 7900 cannot be considered an investment for investment purposes. It WILL depreciate.
Well, then when the time comes, I'll walk out of the house (that i own), into the garage (that i own), and lay the vid cards next to the 2005 2000cc vulcan (that i own) that is right next to the 2004 16FX 160hp jet ski (that i own, and my girlfriend loves to ride)...starting to get the picture?
I'm not really bragging. There are MANY people who make more than I do. I'm sure some of you do. But it's all about "ability".
I just finished setting up my rig (as IN just got the OS loaded tonight).
Basic stuff?
Coolmaster stacker 810
Asus A8N32-Sli Delux
AMD 64 X2 4800 with a Zalmon 9500
2G (2x1) OZC
150G raptor (10K rpm, 16M cache)
250G WD for storage (16M cache)
Two BFG 7900GTX
I broke 8500 in 3dmark06, with zero overclocking or modifications (everything straight out of the box)
Proof Image
Cost? Pretty freaking expensive, and I'm not done yet (going to pick up one of those gateway 21inch widscreens)
Is this the best system out there? NO, not even close. There are plenty of people who have rigs that smoke mine. However, I had fun building it (and not done yet). And THAT is what it's about. What do I enjoy. Well, I enjoy computers (my undergrad is in computer science, my masters in software engineering). I enjoy gamming.
What it really comes down to is if I want to spend MY money on a rig like this, well, I can.
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I should point out that I'm in no way trying to be arrogant. I'm not rich or anything. But I make enough to do/buy the things I want to do/buy.