Mucho Macs 'n stuff

Thursday, March 20, 2008


Well tonight I tried my hand at overclocking, with mixed success. I've been looking up a lot of info on the internet on how to overclock the 733mhz Quicksilver processor that I put in my Digital Audio. Since it doesn't have an L3 cache, it needs it. There's a lot of info out there on how to boost it to anywhere from 800mhz to 933mhz. The best info I found was on this site.
It took me a while to wrap my head around it but it's pretty easy. Basically you need to pull off one of the connecting tabs between two of the lines on the processor. Depending on which ones you modify, by either pulling it off or soldering one shut, you modify the multiplier which in turn modifies the speed. Since I knew I wanted to make the 733mhz processor the end product I decided to practice on the stock 533mhz that came with it. I got a little greedy on this one and went for 667mhz. This also was the easiest modification to do, just clip off one resistor. Well I clipped off one resistor and booted it up. IT RAN!!! For a while. After I put Geekbench on it froze and had to be restarted. On each subsequent restart it would think for along time, then flash a message saying it needed to restart. Rats. So I decided to back it off to a more reasonable 600mhz. This required soldering a resistor bridge. Well my soldering skills aren't the greatest and I ended up making a big mess. I still put it all back together and gave it a shot. Nothing. Wouldn't even boot. I think I soldered it to another resistor.
So with this failure under my belt I decided not to get greedy and keep things simple with the 733mhz. Although I've seen these processors on ebay clocked to 933mhz I decided that a modest boost to 800mhz would be safe enough. I desoldered the resistor and, after putting things back together, it ran! Surprisingly the extra 67mhz DOES make a difference. I ran xbench and geekbench in both Tiger and Leopard. Below are the scores. I'm really surprised that there's almost no difference on the geekbench scores between Leopard and Tiger. I think if I ever try overclocking again it will only be in cases where removing a resistor is necessary. Soldering sucks.

800mhz Quicksilver (in Digital Audio) 768MB RAM
Leopard - 22.02
Tiger - 28.56

Leopard - 433
Tiger - 430

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