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Punkyclown's picture
Joined: 2017 Nov 9
Now on the the next big question - CPU upgrade

Hi All, I have a PowerBook 1400c running at 117mhz. So if I bought
a broken PowerBook 1400c or cs which had a 166mhz processor in it,
does anyone know if it is possible to swap out the CPUs? If I can do
that, what about the L2 Cache is that on the CPU Chip?
Asking a lot, hoping for the best, thanks
Brad Hansen


sfp1954's picture
Joined: 2013 Dec 29

Yes and Yes.
A nut driver would be useful though.
For the four small bolts/screws that hold the CPU in place.

There were also G3 CPU upgrades from other parties (Newertech?).
But don't expect much of performance improvement.
Remember that the CPU speed is a multiple of the bus speed.
So instead of running at 117/33.3=3.5X bus speed you are running at 166/33.3=5X bus speed.

You are still limited by your RAM speed and the speed of your hard drive.
Yes, the CPU is faster, but you can't feed it data any faster than the bus speed allows.

24bit's picture
Joined: 2010 Nov 19

I seem to recall that the 166MHz cpu was incompatible with the 117 MHz PB.
There were of course cpu upgrade sets from Sonnet and others.
Good luck finding such cpu upgrades after all those years.

sfp1954's picture
Joined: 2013 Dec 29

If true - just swap the logic boards - assuming the second machine still boots.

MikeTomTom's picture
Joined: 2009 Dec 7

A CPU change, with Level 2 (L2) cache on-board would be a big improvement.

According to "The Low End Mac", the PB 1400/117 could receive a 30% to 65% speed boost alone with the addition of an L2 cache.

The L2 cache is located on the the CPU of the PB1400/166. But regarding 24bit's comments above, you may also need a motherboard swap if you intend to upgrade the CPU to obtain the L2 cache.

However, in the unlikely (but not impossible) event that you also stumble upon one of the following G3 upgrades, you could also seriously consider a purchase of one of these:

Newer Technology PB 1400 NUpowr G3 Upgrade
Newer Technology PB 1400 NUpowr G3 Upgrade

If the bar in the top row of this spec chart is to be believed, you'd get a huge performance boost Wink

Low End Mac mentions a Sonnet G3/333 with a 512k cache upgrade (erroneously written as a 512 MB cache upgrade) and this could be a possibility if you ever see one. Either of these solutions however, would likely be a rarer find than finding the PB 1400 itself...