Recently, Robert Marshall posted some information about increasing the clock speed of his 3400/180 to 198 MHz using a 44 MHz crystal to clock the bus. (The standard bus is clocked at 40 MHz). The performance increase was very impressive, and there has been a great deal of interest in the PowerBook 3400 community for a kit that can be used to speed up the bus (and CPU) clock. Since we had provided the crystals to Robert, we've been getting a large amount of email asking if we can sell these crystals to other interested parties.
First, some background. The 3400 models all have a 40 MHz bus clock and the different CPU speeds are obtained using a different multiplier of the bus clock:
| Model | bus clock | multiplier | CPU clock |
|---|---|---|---|
| 3400c/180 | 40 MHz | 4.5 | 180 MHz |
| 3400c/200 | 40 MHz | 5 | 200 MHz |
| 3400c/240 | 40 MHz | 6 | 240 MHz |
Speeding up the CPU is as simple as replacing the bus clocking crystal with a faster crystal. Our kit for the 3400/180 includes 48 MHz and 50 MHz crystals, while the kit for the 3400/200 includes 44 MHz and 44.736 MHz crystals. (Both kits include a 2-pin crystal socket). We chose these speeds after testing them on these models, and the performance you can expect depends on which model of 3400 you started with. We don't have enough data on how fast the 3400/240 can run to offer a kit for that machine, but if you want to order crystals to do your own experimentation, this table should be somewhat helpful. The 3400/180 and 3400/200 both max out at around 225 MHz, so we don't expect a huge increase for the 3400/240:
| Crystal | 3400c/180 will run at: | 3400c/200 will run at: | 3400c/240 will run at: |
|---|---|---|---|
| 44 MHz | 198 MHz | 220 MHz | 264 MHz |
| 44.736 MHz | 201.312 MHz | 223.68 MHz | 268.416 MHz |
| 48 MHz | 216 MHz | 240 MHz | 288 MHz |
| 50 MHz | 225 MHz | 250 MHz | 300 MHz |
The price for the 3400/180 and 3400/200 kits is $10. We can sell you a Torx T-8 wrench to open the case for another $2. There is a $5.15 shipping charge, and 8.25% sales tax must be added to the kit price for shipping addresses in California. The easiest way to order a kit is to visit our secure online order form
Upclocking your computer will void any warranty you may have with other hardware vendors. Not all computers can be upclocked, and the top speeds attainable through upclocking can vary widely for a single model. This modification requires you to do some amount of soldering on your motherboard, and you will be responsible for all damage and repairs should something go wrong.