The 9550 is a good CPU and can do some decent overclocks. Of course when you can double your cores and get extra speed, you'll see a difference.
How long will it increase your future-ability? Well, technically you are already obsolete by at least 3 new 'techs', but really, your CPU is useful until it burns out or your needs outgrow it. No one can really say (except maybe Intel) how long the 775 fabrication process will be useful/programs made for.
Case in point, my HTPC still runs an old AMD 4850e, but it continues to do the job. It doesn't get gamed on so I forsee it's ability to run movies through HDMI to last until HDMI no longer exists!!
true it's a little long in the tooth but for my personal gamer I swapped out an annoying 6850 dual core for the q9550 ( several years ago.... ) . Real good move it was. The dual core was almost obsolete for my needs when I purchased it and soon became annoying to have. Big difference in performance with the extra cores and cache. If you're getting it for nothing it's a no brainer.
right now it's the limiting factor in my machine and it will soon need to be upgraded.
You might be able to squeeze out around two years perhaps more if you keep up to date when it comes to the drives. This cpu can handle mid range cards without any noticeable loses compared to newer build but that is all. Overall it is good enough for most games cpu wise but the board does hold things back a little even for 775 but not terribly.
Bad news. According to the nVidia site, the Q9550 (or any 45 nm quad) is not compatible with the nForce 600 chipset.
My experience with my eVGA 680i motherboard indicates that is true.
that almost sounds too insane to be true. makes me rethink future purchase. I don't buy high end cards for myself anymore but this would also translate into mid-range cards ? wacky..... are these pci-e 3.o interfaces ? and is that why ? please post link. need to educate myself.