You will not be able to upgrade to a Core 2 Duo. Although your motherboard has the correct socket, it does not have a supporting chipset. If you want to upgrade your processor, you will need a new motherboard with a 975X or 965 chipset (and make sure it is compatible with the rest of your components!) As for performance gain, it will be considerable if you do upgrade, but it'll be expensive also.
Core 2 is a significant upgrade. it has around double the performance/GHz as compared toa celeron D, then it's dual core. Long story short there is a great potential for performance gain. but is your motherboard compatable? if not just forget it a 3.066GHz Celeron D is probably good enough for now, otherwise you'de eb buying a new CPU, a new motehrboard and potentially a few other parts. also, chief nx, beleive it or not, some 945 chipsets and even some 875 chipsets have c2d support.
Don't see how you can game on that rig, I have almost the same build and I can barely load BF2142. Your mobo doesn't support C2D and you'll definately want a Gig of RAM and a new graphics card. So you'll need: New PSU New Processor New graphics card New motherboard New memory If you plan on gaming. Don't go with the 8800 either, wait for r600 core.
No, a BIOS flash will only SUPPORT the CPU. It cannot run at the full FSB, which is 266Mhz (P4 FSB = 200Mhz). I suggest getting a new MOBO. But youre fine for now with a P4 3.06Ghz
not if the motherboard isn't properly configured for the diferent voltage regulation used by c2ds. Some revisions of a board support c2d while other revisions do not. It is often finicky and there is a lot fo grey water for trying to determine compatability. I do beleive that the 3.066GHz celeron Ds with 512mb l2 cache are pretty new, so the probability of motherboard comptability is a bit higher... why not just OC the celery though? set the bus speed to 667 and it effectively sets your celery D to 3.8GHz... Personally a new GFX card would benefit you more than a new CPU, that celeron is probably fine as is for most things.
For a upgrade? I dont know what case and PSU you've got, but if you're willing a better VGA you'll need a new PSU anyways. All I can suggest for now, for a small upgrade, buy another 512mb stick. If you want to spend more money, you will probably want a better VGA > 8800GTS > Needs PCI-E > NEW mobo> Old PSUs dont support new mobo> NEW PSU > New mobo needs new ram > etc. You'd be spending much more.
