I am afraid that my Intel Core 2 Quad Q9400 (2.66 GHz) will bottleneck a single GTX 285 or HD 4890. It's probably already bottlenecking the HD 4850 it has in there right now. My relatively wealthy parents are extremely frugal, and I was lucky as heck to get the computer that I did. Knowing from experience, I probably will not be getting another one for many, many years. I am also terrified to overclock my processor because I have been told that overclocking can be extremely dangerous if you do not really know what you are doing. I'd like to overclock my C2Q Q9400 from 2.66 GHz to 3.00, which is a 340 MHz overclock. It is using it's stock cooler air cooler, which are not very good from what I have heard. Overclocking can cause your computer not to boot, constantly crash, become unstable, overheat, corrupt your system, etc... It requires an expert knowledge of computer science and electronic engineering to do so safely and correctly. Besides, I don't believe that my PC came with any type of CPU overclocking software whatsoever. If I overclocked, it would the warranty would probably instantly be completely voided if I moved the slider left or right.
My Radeon HD 4850 idles at about 90 degrees celcius, and operates at 100-120 under load with it's stock cooler. Can I run my C2Q from 2.66 GHz to just 3.00 with it's stock cooler? I mean, it's not like I'm clocking it to 4.0 GHz or anything.
Oh, and I don't know if a GTX 285 will fit in my case. I believe it would be blocked by the extra hard disk bays that I will probably never use. I have never actually seen a GTX 285 so I wouldn't know how large it is. I have also never taken any measurements of the inside of my case and compared them to the dimensions of the upgrades I want to see if they would physically fit. I was thinking about getting a Fatal1ty X-Fi gaming sound card and the "Killer NIC M1" gaming network card but the PCIe x16 and either the PCIe x1 or the PCI slots are too close to each other and probably, from my guess, would not fit. With pre-built, budget gaming computers, companies usually throw in cheap motherboards, power supplies, etc to keep the price down.
I would take a picture of the inside of my computer with my digital camera and post it here but my brother currently has it and I would have to get it back from him.