G3 Upgrades for Power Mac 7600 and 8600

1998 – MS writes: I own a Power Mac 7600/120 and am interested in boosting performance. I currently run on a 604 with 112 MB RAM and 1 M L2 cache. Would you recommend migrating to a G3 or a 604e?

I have been looking at 300/1M L2, but the price is a bit high right now. Is there a great deal of difference in performance between a 220 MHz 604e and a G3 220 MHz? Can I still use my L2 cache with the 604e, and what are the benefits vs. a G3.


PowerPC G3 CPUMac Daniel writes: I had a 7600/132 for about a year before upgrading to a 180 MHz 604e, then a 200 MHz 604e with 1 MB L2 cache. Each upgrade made a very nice improvement in performance.

Our Guide to G3 Daughter Cards shows there are more G3 upgrades for your 7600 than you can shake a stick at. Any one of them would provide a lot more speed than a 220 MHz 604e. The G3 is a newer CPU with a design optimized for the way Mac software works, so at the same MHz rating, it will outperform the 604e.

I recommend replacing your 120 MHz 604 with any G3 card. Basically, set a budget and find a card to fit it. I recommend you pull the 1 MB L2 cache, since the G3 card will have a much faster L2 cache. You should be able to sell the pulled cache – and possibly even the 120 MHz card – which will help reduce overall cost of the upgrade.

And when you find a 233-266 MHz G3 isn’t fast enough, those really fast G3 cards should be much more affordable.



CN writes: I have a Power Mac 8600/200, 32 megs of RAM, and stock cache (256 KB?). I would like to speed it up and was thinking of adding another 32 megs of RAM plus 1 meg of cache and maybe a 7200 rpm hard drive. After adding it all up, I notice that I am in the range of a G3 upgrade. What are your thoughts?


Mac Daniel writes: I run a 7600/200 at work with a 1 MB L2 cache. I can’t believe how much faster it feels than my 7600/180 with 256 KB L2 cache, so if you’re not going to put in a G3 card (which will have its own 512 KB or 1 MB L2 cache), a 1 MB L2 cache is worth serious consideration.

Extra memory is always a plus, but you might want to postpone that a month or two – memory prices traditionally fall, except for a glitch every two or three years that raises prices. We’re in one of those times right now. The same 64 MB DIMM I once bought for under $70 sells for over $100 today.

If you do buy a 7200 rpm drive, be sure to mount it internally so you can use the faster internal SCSI-2 bus. You won’t see nearly the same boost in throughput on a SCSI-1 bus, which is what Apple uses for external drives.

With G3 cards starting under $400, and a 1 MB L2 cache usually over $100, that option merits serious consideration. See our Guide to G3 Daughter Cards for an overview of speeds, cache sizes, and approximate costs.



Jayne writes: I have a Power Mac 7600 with the 120 MHz 604 chip; 80 MB RAM, and 1.2 GB hard disk. I would like to use it as an occasional video editing machine.

Is it worth the while to upgrade? Is G3 upgrade viable?


Mac Daniel writes: I haven’t done any work with video, but I can imagine it would tax a 120 MHz 604e. With some G3 upgrades selling for under US$400 these days, I think buying a G3 card would be a wise choice.

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