Can i upgrade a single 1GHz model to a dual 1GHz or a dual 1.25GHz cpu with no issues?
A 1.25GHz Dual board from a FW800 will work fine on any FW800 motherboard, no matter if its speed is 133MHz or 167MHz. However, on a 133MHz motherboard it will be underclocked and function as a 1.0GHz Dual processor machine. If one wants the full 1.25GHz Dual speed then a resistor on the back of the motherboard (not cpu daughtercard) must be removed.
I performed this upgrade on my wife's single 1.0GHz FW800 about a week ago. It's an easy, plug and play swap. Removing the resistor is another matter--they are extremely small. I plan to do this at some point, but for now my wife is happy with the already noticeable speed increase.
As far as the heatsink is concerned, the heatsink with the many flexible fins is the one which originally shipped with the FW800 1.25GHz Dual machine. The copper one came with the 1.42GHz Dual. As far as I know, the other heavier aluminum heatsink came with the original MDD's and the FW800 single 1.0Ghz model. My wife's 1.0Ghz single came with this one, but I changed it out for the flexible finned one which came with the dual daughtercard I purchased on eBay.
Every FW800 1.25GHz Dual I have ever seen (and that's more than a few) have had the flexible finned heatsink. While it may not look as substantial as the solid aluminum finned one, because it has many more fins it should provide better cooling. In any case, it came this way from the factory in my 1.25GHz Dual FW800.
As an aside, my wife's FW800 operates 10 degrees F cooler than mine. I assume because it is running at the slower speed. The machines are using Tiger 10.4.11 and setup identically.
As always, I am not trying to dispute anyone else's posts or opinions on this forum, just relating my own experience. Oh, I see I have to change that signature now.
