The important question is how long do you plan to hang on to your G4?
By October or so we should have power macs with 970 CPUs out and then even the low end will be faster than dual 1.42. If you plan to have your computer for a year the dual will only cost you 2 dollars a day and the 1.2 even less quite a good deal. But if you plan to buy a 970 the day they are out 600-800 dollars spent on a G4 upgrade is quite a sizeable chunk out of the price of a complete computer...
so, the few extra mhz and the L3 cache is worth it?
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My rule of thumb is that if a computer is to slow an upgrade of less than twise the performance will be to slow as well. The 50% speed increase and the L2 should get you pretty close to that doubled performance.
The cache is very important. Not only does it affect speed of execution but also the delay beween order and start of work. ( I had a Impact Extrem 030 accelerator with a 32k L2 that could be truned on and of in hardware, and I also have tried PCI PPCs (90 MHz 601 to 200 MHz 604E, They all were affected by that irritation delay without the L2)
i kinda feel silly upgrading from 800 to 1.2 (limitation of my machine - can't go to 1.3)
Dual 1.2 is sweet!
is the graphics card even an issue?
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No it is not and I think you have a Radeon 7500 OEM card. For 2D it really does not matter what card you have
i play no games.
With a graphcial card that is plenty fast and a lot of RAM I would go for the upgrade if I plan to use the computer for a year or more