Early 05 Dual 2.7 G5 - Come see my wall of text! (4 main questions)

Question

Hi all,
I obtained my Early 2005 Dual 2.7 G5 from my dad. It served 4 years as his drawing and rendering machine (he designs and builds custom cabinetry & furniture).
I have been trying to get it running well enough to play Civilization 4: Beyond the Sword, and have had problems from day one.
OS-10.2.9 (have a 10.3 disk, but it's scratched, ok so I guess I don't have a 10.3 disk..)
8GB Ram - One of my questions pertains to this.
GFX Card - ATI Radeon 800XT - I realize this may be a source of problems, but I'm pretty sure I installed it properly(had good help), and the same symptoms that persist were there before and after.
Symptoms:
- fans run erraticly. Ramp-up to full very quickly, then scream like a jumbo jet, then stop suddenly, sometimes in-line with processor load (videos, aperture edits, launching Civ4, making Civ4 maps), and sometimes without any discernable reason.
- runs Civ4, but extremely slow (at least I'm expecting more, I ran Civ4 on a PC with way less "power" and had similar if not better performance)
- no coolant leakage. I read that this is a very common problem (though moreso with earlier liquid-cooled models). I removed the cowl, shone a flashlight into every cranny I could looking for crystalized coolant, but didn't find any (phew!). (I realize it's not a symptom, but it seemed topical.)
- self shut-off. Happens whenever I try to run Civ4 without first changing the energy saver processor setting to 'reduced'. Has also happened while surfing the web (gifs seem to be a killer...)
Questions:
1- Is my 300GB Velociraptor (WD3000GLFS) causing me problems? I read in my forum browsing that there may be compatibility problems when using these drives in this model of G5 without an additional Sata card. I happen to have one of these cards, as my dad used to run 6 seperate drives in this machine, but I'd rather not have to install it again, as I've already split the optical drive power to power the 800XT graphics card, and iirc, additional power is needed for the SATA card (or was that for the drives themselves...I forget).
2- Is there a map or schematic somewhere for the heat sensor locations? I'm intending on going to town with cans of compressed air in case dust is resulting in faulty readings, causing the fans to operate erraticly, and overtemp readings which cause the computer to shut itself down. (I think there is fine saw dust hiding in the optical drive that pops-out again even after I've cleaned it (which I have done before, in a way I thought was thorough...)
3- Is there anything wrong with using RAM from different manufacturers? I currently have:
OWC 3200 DDR 1024 x4
Kingston KVR 400x64 C3A/1G x2
MT16VDD...1 GB DDR, 400, CL3 (I think these may have been the stock ones) x2
4- I'm thinking of purchasing a wireless card, if I can get the thing rolling to my satisfaction. Would an Airport Extreme card do the trick? Would that handle Bluetooth devices as well? Ok I don't own any bluetooth devices, but newer mouse/keyboards use it? (I think?).
Thank you all for reading, any help would be very much appreciated.
The more I learn, the more I realize how much of a newb I am.
Gorf

Answer 1

Yarrr... yes sir I read it yesterday. This is why I dug so carefully for coolant leaks. Unless it's all leaked out without leaving a trace, I think I'm at least clear on that front for now. Though I hate how my fan and shut down troubles fit with the symptoms of some of those writers. Is it challenging to disconnect the CPU/LCS assembly for inspection as he describes? My 'call the tech' warning screeches loudly on that one.
So I'm back up and running now and the slot fan is still at 76 rpm. I also realized there is a 'backside' fan which was previously hidden by the size of the display window. It's sitting at 51rpm.
Are these fan controls something that could be remedied by reinstalling the OS?