This is a close call. Let's start with: "i've been using my QS a lot and it's doing great."
*That lessens the priority a LOT right there.
QS is 867. That means a 133 bus.
* Same bus on MDD UNLESS it's a dual 1.0gHz, then it's 167 mHz BUT that's switchable on the motherboard.
You hear MDD's are noisy.
* You hear correctly. MDD fan noise is a serious pain in the ass. Personally, I actually gave up and built a complete "quiet box". Of course, I then had to install fans in THAT which also make noise. Eventually you're a dog chasing his own tail.
QS memory compatible with MDD?
*No.
PCI compatibilty.
* 100% not a problem
* If it is a dual, they probably would have said so. Note however, a single 1.0gHz is probably a "Firewire 8oo" model which will require the special OS9.2.2 we have for it. No big deal otherwise.
* Note also you CAN (not necessarily should, but can) buy any MDD and dink around with different CPU boards. They are ALL interchangable, so you can "build up". Assuming you have nothing better to do of course.
* Oh yeah… As often as not, your "new" computer will arrive damaged because NObody uses common sense packing and shipping heavy electronics. There's a reason they have those elaborate styrofoam molded protection thingies. When they're gone, shipping becomes a HUGE risk.
This is where I go back to the top: "i've been using my QS a lot and it's doing great"
If it was me, I wouldn't fix what ain't broke.
Gary