This page was archived in 2023 as part of the Mac Hut archive and is no longer updated.

Most of the site pages were last updated around 2003-2004, as such various information may be out of date. The forum and equipment for sale sections have not been archived.

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Spec Comparisons on 6400/6500 L2 G3 Upgrades

This page will be used as a reference for the specs on all L2 G3 cards for the 6400/6500. Since the manufacturers have made trying to tell exactly how a particular card will run on the different speeds of system buses difficult, I thought this page needed to be made. Remember that all other models based on the same motherboards should have the same specs. The green text denotes the fastest available G3 for a particular system. The red text denotes cards not in production anymore :(

Below the chart are some misc. G3 upgrade card info as well that apply to all L2 G3 upgrades so I posted here instead of on each individual cards page.

Return to The 6400 Zone Home page

* Note, these are only for the 4400,7220, and Starmax clones

CPU / cache Speed in 40Mhz bus 6400 CPU / cache Speed in 50Mhz bus 6500 cache size listed retail price current CPU technology double boots Compatible with Geo
Vimage 240 240Mhz / 120Mhz 225Mhz / 112Mhz 512k out of business non-copper Motorola yes with OS 8.1 and up
Vimage 320/325 320Mhz / 160Mhz 325Mhz / 162Mhz 1M out of business copper yes with OS 8.1 and up
Sonnet 250 240Mhz / 120Mhz 250Mhz / 125Mhz 512k discontinued non-copper no some issues
Sonnet 300/512k 300Mhz / 150Mhz 300Mhz / 150Mhz 512k discontinued * copper no some issues
Sonnet 300/1M 300Mhz / 150Mhz 300Mhz / 150Mhz 1M discontinued copper no some issues
Sonnet 320/350 512k 320Mhz / 160Mhz 350Mhz / 175Mhz 512k discontinued copper no some issues
Sonnet 320/350 1M 320Mhz / 160Mhz 350Mhz / 175Mhz 1M discontinued copper no some issues
Sonnet 400/512k 400Mhz / 133Mhz 400Mhz / 133Mhz 512k discontinued copper 10x bus no some issues
Sonnet 400/1M 400Mhz / 200Mhz 400Mhz / 200Mhz 1M $199.95 copper 10x bus no most issues resolved
Sonnet 500/1M ? 500Mhz / ? 1M $249.95 copper 10x bus no most issues resolved
Newer 300/512k 300Mhz / 150Mhz 300Mhz / 150Mhz 512k out of business ? no modem port errors
Newer 300/1M 300Mhz / 200Mhz 300Mhz / 200Mhz 1M out of business ? no modem port errors
Newer 400/1M 400Mhz / 200Mhz 400Mhz / 200Mhz 1M out of business copper no modem port errors
PowerLogix 240/512k 240Mhz / 120Mhz ? 512k vaporware! non-copper no ?
PowerLogix 320/1M 320Mhz / 160Mhz ? 1M vaporware! ? no ?
PowerLogix 400/1M 400Mhz / 160Mhz 400Mhz / 160Mhz 1M vaporware! copper 10x bus no ?

Sonnet / Geo Issues: To help solve issues with the Geo modem try renaming the Crescendo extension to zCrescendo to make it load later. Make sure you have Apple Telecom software 3.1.3 which is the latest version and mandatory with any version of Mac OS 8.x. Try rebuilding the desktop file again as the Sonnet installer forces a rebuild which doesn't always work properly. Please report any issues you have and also include the version of the Crescendo extension you have.

The latest Crescendo driver 1.3.7 seems very stable. UPDATE: The 1.4.1 driver has gotten rid of the startup crashes!

Newer / Geo Issues: try the above suggestions for Newers G3 software and see if it helps. Please report any issues you have and also include the version of Newer's extension you have.

Mac OS 8.6 compatibility: Both Vimages and Sonnets G3's are now OS 8.6 compatible. Visit their web sites to get the latest drivers. Newers was already OS 8.6 compatible.

L2 G3 Performance Comparison page: Donato sent me this link to a page with a lot of bench mark numbers on all the current L2 G3 upgrades.

Apples PCI Timing Extension to help fix L2 G3 audio issues: I have had several reports now that the PCI Timing Extension made for Power Computings clones help fix instability with audio apps on L2 G3 upgraded Macs.

Audio/Video Stuttering issues - Click here to read all I have on these issues. They may not be caused by the G3 upgrades but many more people with G3 upgrades have these problems then people without G3 upgrades.

4/27/2002 Info from Ralph on cooling the RAM chips in a G3 upgraded Mac to make it more stable: Ralph also sent info on how to cool your RAM chips to make your G3 upgraded Mac more stable. Thanks Ralph.

[Now if you want to help the Sonnet using community here is a tip to get better and longer use out of these things. In a PM5500 and PM6500 heat is a problem. The L2 G3 board is right up against the RAM. I have found RAM to be heat sensitive if the Sonnet metronome software indicates it goes over 40'C. The Sonnet can handle much higher temps, I use to see 47'C sometimes with running QT movies, and it ran fine, but the RAM got a little funny. So I recommend that if you have these machines and use the L2 G3 upgrades, especially the PM6500 (its L2 mounting puts the heatsink opposite convection flow) is to buy two socket 7 pentium cooling fans, remove the heatsinks (t451-2020 $7 each from They are 12 volt and each pulls about the same current as the stock apple fan. Take the Apple processor fan off and using its mini plug solder the two 7 fans in its place. Run the two pentium fans in series so they split the voltage and run at half speed and draw the current of one Apple fan to avoid overtaxing the Apple supply (wire the first fan red wire to the mini plug red and the other fans black to the Apple plug black and connect the remaining 7 fans red and black to each other). Using nylon ties to attach them, put one over the stock apple processor and one blowing down (the side of the fan that was next to the heatsink is the direction the fan blows) over the L2 G3 and Ram. On the 5500 you have to mount the fan in the back of the L2 and blow it toward the edge of the L2 G3 and RAM. On the 5500 before you cut the Apple fan wired make sure you can fit the 7 fan in back of the L2 by attaching it to the L2 sonnet board with a nylock and put it back into the case. These 7 fans are larger in dia so some custom placement is necessary. Since after extensions boot, the Apple processor goes to idle with the L2 G3 taking over, the slower fan speed over the Apple processor is not important. If you have to go back to the Apple processor for any length of time, than just run the socket 7 fans at full speed by rewiring them in parallel. The socket 7 fans are larger and even at half speed move plenty of air so the above should not be necessary.

Once this is done, your L2 G3 will run about 10'C cooler and you can try overclocking it a bit. More importantly if you have RAM that does not like higher temps you can get less system lockups :)]

7/20/03 Sonnets latest G3 upgrades are more stable then previous versions: Sonnets latest 400Mhz and 500Mhz G3 upgrades are the most stable of the lot. There may still be some issues such as audio stuttering when mixed with their original Firewire/USB combo card but the heat sink is smaller so it no longer touches the RAM chips its sitting next to and other stability issues have been resolved with the latest software. One issue that may not be an issue is the fact that neither can be clocked with the Sonnet Clocker anymore? They appear to be hard coded at their speeds. The only issue would be a person putting the 400Mhz model in a 6500. It will only run at 400Mhz and won't allow you to over clock it by changing the bus multiplier as previous Sonnet G3's could. But in a 6400 the 400Mhz card is already at maximum speed and the 500Mhz card is at maximum speed in a 6500 so there really is no way to overclock them even if it was possible!

L2 G3 Reported Temperatures

My Vimage Info page on Vimage's G3 upgrade for the 6400

My Vimage Compatibility page
My Vimage User Letters page
My Vimage install reviews

My Sonnet Tech Info page on Sonnet's G3 upgrade for the 6400

Hack to make Sonnets G3's more stable
My Sonnet Compatibility page
My Sonnet User Letters page
My Sonnet install review

My Newer Tech Info page on Newer's G3 upgrade for the 6400

My Newer Compatibility page
My Newer User Letters page

My PowerLogix page on PowerLogix's G3 upgrade for the 6400

Return to The 6400 Zone Home page

If any of the links do not work properly, please send an email to me the Site Master
This page last updated 7/20/2003