Power Macintosh

Guide to CPU Upgrades for AGP G4 Power Macs

Updated 2008.06.04

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The Power Mac G4 started life as a powerful computer, but some are already five years old and could use a speed boost. Although more memory and a faster hard drive can improve system performance, replacing the old G4 with one or two newer, faster G4 processors is just the ticket for processor-intensive work.

Current CPU upgrades range from 550 MHz to 1.5 GHz, and dual processor models offer speeds to 1.33 GHz.

Upgrades on this page may work in any of the following models. Be sure to check manufacturer specifications for full compatibility details. The following numbers are used in the tables below to noted compatibility. At this time, only Sonnet makes CPU upgrades for the 1.25-1.42 GHz MDD models that have a 167 MHz system bus.

  1. G4/350-500 Sawtooth/AGP graphics - 100 MHz bus
  2. G4/450-500 dual processor - 100 MHz bus
  3. Cube - 100 MHz bus
  4. G4/466-533 (digital audio) - 133 MHz bus
  5. G4/667-733 (digital audio) - 133 MHz bus
  6. G4/733-867 (Quicksilver) - 133 MHz bus
  7. G4/800-1 GHz (Quicksilver 2002) - 133 MHz bus
  8. G4/867 MHz dual (Mirror Drive Door) - 133 MHz bus
    G4/1 GHz (FireWire 800) - 133 MHz bus
  9. G4/1-1.25 GHz GHz dual (Mirror Drive Door) - 167 MHz bus
    G4/1-1.42 GHz (FireWire 800) - 167 MHz bus
    G4/1.25 GHz (June 2003) - 167 MHz bus

The information is as accurate as I can find, but specifications and availability are subject to change; I suggest you check with the manufacturer to verify current models. Prices keep dropping, so these prices may be outdated. (Prices are in $US.) In fact, models are added and discontinued so often, it's impossible to keep track of which models are current.

NOTE: These upgrades are not compatible with the Yikes! G4. See our Guide to G4 ZIF Upgrades for Power Mac G3 and G4 "Yikes!" models.

Discontinued accelerators are listed for historical reasons. On dual processor upgrades, cache size is per processor.

The PowerPC 7451 and 7455 have an internal 256 KB level 2 cache. The 7447 and 7457 have 512 KB. The 7448 has 1 MB. All else being equal, the bigger cache will make upgrades a bit faster.

CPU
Speed

L3
Cache

Cache
Speed

CPU

Estimated
Street Price

Giga Designs, CPUs may be overclocked
Compatible with 1, 2, 4, 5, 6, 7 - see site for details
1.2 GHz 2 MB 240 MHz 1.0 GHz 7455 disc.
1.4 GHz 2 MB 233 MHz 1.25 GHz 7455B $219
1.467 GHz 2 MB 244 MHz 1.25 GHz 7455 disc.
1.5 GHz 2 MB 250 MHz 1.25 GHz 7455 disc.
1.53 GHz 2 MB unknown 1.53 GHz 7455B $249
1.6 GHz 1.6 GHz 7447A disc.
1.8 GHz 1.8 GHz 7447A disc.
dual 1.2 GHz 2 MB 240 MHz 1.0 GHz 7455 disc.
dual 1.3 GHz 2 MB 222 MHz 1.25 GHz 7457 disc.
dual 1.33 GHz 2 MB 280 MHz 1.25 GHz 7455B disc.
dual 1.4 GHz 2 MB 280 MHz 1.25 GHz 7457 disc.
dual 1.7 GHz 1.7 GHz 7447A disc.
dual 1.8 GHz 1.8 GHz 7447A disc.
For the Cube
1.33-1.5 GHz 2 MB 222-250 MHz 1.33 GHz 7457 disc.
For Mirrored Drive Door
1.33 GHz 2 MB 167 MHz 1.33 GHz 7455B disc.
1.4 GHz 2 MB 233 MHz 1.25 GHz 7455 disc.
Newer Technology MAXPower G4/7447A, MAXPower G4/7448
Compatible with 1, 2, 4, 5, 6, 7
1.6 GHz 512 KB 1.6 GHz 7447A $230
1.6 GHz dual 512 KB 1.6 GHz 7447A $400
1.7 GHz dual 512 MB 1.7 GHz 7447A $500
1.8 GHz dual 512 KB 1.8 GHz 7447A $600
1.8 GHz 1 MB 1.8 GHz 7448 $340
2.0 GHz 1 MB 2.0 GHz 7448 $399
1.7 GHz dual 1 MB 1.7 GHz 7448 $599
1.8 GHz 1 MB 1.8 GHz 7448 $699
Other World Computing Mercury Extreme
Compatible with 1, 2, 4, 5, 6, 7
867-933 MHz 2 MB 173-233 MHz 7455A disc.
933 MHz-1.0 GHz 2 MB 233-250 MHz 933 MHz 7455A disc.
1.0 GHz 2 MB 233-250 MHz 1.0- GHz 7455A disc.
1.2 GHz 2 MB 240 MHz 1.0 GHz 7455 disc.
1.2 GHz 2 MB 240 MHz 1.2 GHz 7455B $199
1.25 GHz 2 MB 250 MHz 1.25 GHz 7455A disc.
1.25-1.33 GHz 2 MB 208-222 MHz 1.25 GHz 7455B disc.
1.4 GHz 2 MB 233 MHz 1.33 GHz 7455B disc.
1.467-1.5 GHz 2 MB 245-250 MHz 1.5 GHz 7455B $260
Operator Headgap Used, sometimes overclocked Apple CPUs
Compatible with 1, 2 (single-processor model only)
400 MHz 1 MB 200 MHz 400 MHz 7400 $12.77
500 MHz 1 MB 250 MHz 450/466 MHz 7400 $24.77
550 MHz 1 MB 275 MHz 466 MHz 7400 $49.77
600 MHz 1 MB 600 MHz 533 MHz 7410 $39.77
PowerLogix PowerForce G4 Single CPU
Compatible with 1, 2, 3, 4, 5, 6, 7
800 MHz 2 MB 250 MHz disc.
1.2 GHz 2 MB 200 MHz 1.0 GHz 7455 $179
1.4 GHz 2 MB 250 MHz disc.
1.6 GHz 2 MB 250 MHz 1.2 GHz 7447A $439
PowerLogix PowerForce 47/55
Compatible with 1, 2, 4, 5, 6, 7
1 GHz 2 MB 200 MHz 7455 $160
1.6 GHz 7447A $220
1.2 GHz dual 2 MB 250 MHz 7455 $300
1.6 GHz dual 7447A $429
1.7 GHz dual 7447A $449
1.8 GHz dual 7447A $629
PowerLogix PowerForce G4 Series 100
Compatible with 1, 2, 3; $10 more for Cube fan kit
700 MHz 2 MB unknown disc.
800 MHz 2 MB 250 MHz disc.
1 GHz 2 MB 250 MHz disc.
1.2 GHz 2 MB 250 MHz disc.
PowerLogix PowerForce 47/48 for Cube
Compatible with 3
1.5 GHz 512 KB 7447 $250
1.7 GHz 1 MB 7448 $370
1.5 GHz dual 512 KB 7447 $450
1.6 GHz dual 7447 512 KB 7447 disc.
1.6 GHz dual 7448 1 MB 7448 $680
PowerLogix PowerForce G4 Series 133
Compatible with 4, 5, 6, 7
733 MHz 2 MB unknown disc.
867 MHz 2 MB 250 MHz disc.
1 GHz 2 MB 250 MHz disc.
1.6 GHz 7447A disc.
PowerLogix PowerForce Dual G4 Series 100
Compatible with 1, 2, 3
"Early models of AGP have a bridge chip that is not compatible with dual processors. We recommend the PowerForce G4 Series 100 (single processor) for those machines."
800 MHz 2 MB 250 MHz disc
900 MHz 2 MB 250 MHz disc
1 GHz Dual 2 MB 250 MHz 7455 disc.
1.3 GHz Dual 2 MB unknown 7455 disc.
1.6 GHz Dual 7447A disc.
1.7 GHz Dual 7447A disc.
1.8 GHz Dual 7447A disc.
PowerLogix PowerForce Dual G4 Series 133
Compatible with 4, 5, 6, 7
"The PowerMac G4 Cube has a lower capacity power supply and therefore we conservatively recommend installing at most a Dual 800 MHz."
867 MHz 2 MB 250 MHz disc.
933 MHz 2 MB 250 MHz disc.
1 GHz 2 MB 250 MHz disc.
1.2 GHz 2 MB 250 MHz 7457 disc.
1.33 GHz 2 MB 250 MHz 7457 disc.
1.6 GHz 1.25 GHz 7447A $429
1.73 GHz 1.42 GHz 7447A $499
1.8 GHz 1.6 GHz 7447A $629
Sonnet Encore/ST G4
Compatible with 1, 2, 3, 4, 5, 6, 7
800 MHz 2 MB 400 MHz 7455 disc.
1 GHz 2 MB 500 MHz 7455 $170
1.2 GHz 2 MB unknown 7455 disc.
1.4 GHz 2 MB unknown 7457 disc.
1.6 GHz 7457 disc.
1.7 GHz 7457 disc.
1.8 GHz 7457 $270
Sonnet Encore/ST G4 Duet
Compatible with 1, 2, 3, 4, 5, 6, 7
500 MHz 1 MB 250 MHz 7455 disc.
1.267-1.3 GHz 2 MB unknown 7455 disc.
1.6 GHz 2 MB unknown 7447A disc.
1.8 GHz 2 MB unknown 7447A $500
Sonnet Encore/MDX G4 Duet
Compatible with 8, 9, and G4 Xserve
1.6 GHz 512 KB 7447A $450
1.8 GHz 512 KB 7447A $600
XLR8 MACh Speed G4 Sawtooth
Compatible with dual G4/450 and 500 only.
500 MHz 1 MB 250 MHz 7410 disc.
550 MHz 1 MB 275 MHz 7410 disc.
XLR8 MACh Speed G4 ZIF MPe
Compatible with dual G4/450 and 500 only.
350 MHz disc.
400 MHz disc.
450 MHz disc.
500 MHz disc.
550 MHz disc.

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