L2 G3 Reported Temperatures

I have provide this page for all the users that are wondering what the temp of their particular L2 G3 relatively run at. Note that Sonnet has redesigned their L2 G3 cards a year ago or more and the new cards have a slightly smaller heat sink so they get a little warmer then before. Previously the 300Mhz card ran in the 30's to low 40's and now they run in the low 40's to low 50's. If you have a L2 G3 that is not posted here, please send me your temp readings in celcius, Thanks.

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This chart shows the temps of the L2 G3 cards I reviewed in my 6400

CPU speed (Mhz) /cache
Temp (C)

Temperatures of 400Mhz L2 G3 upgrades? 7/21/2001

Bryan would like to know what the average temp of 400 Mhz upgrades are running at. I wasn't able to test any of these so if any of you could email me this info, I would greatly appreciate it :)

[Having visited your site numerous times I have come to appreciate you opinion. I would like your opinion on my situation. I recently purchased a Newer Tech G3 L2 400 MHz upgrade. The speed is phenomenal but I worry about the temperature. On the first day I watched the temp on Newer's Gauge PRO climb to 91 C. I shut down and let the computer cool off. Since then I have installed a fan on the heat sink which maintains an average between 60 to 70 C. Right now it's at 66 C.

I really need to know if that's ok for my machine. I do not want to cook anything as I've just invested a considerable amount of money on hard drive and RAM upgrades. What do you think?

8/4/2001 Update on temperatures seen with L2 G3 upgrades: below are several letters I received from readers with there findings on L2 G3 temps.

The temp was 60-65C with my Crescendo 300mhz....in my 6500...
When I installed the NewerTech 400mhz temp dropped to 48-55c... I think because the heat sink is exposed to the processor (and the fan,) rather than the ram,

[Aloha Tom,
Per Sonnet technicians (I know, your discussing Newertech), their upgrades will run fine up to 80 degrees Celsius, but he would not recommend that, my Sonnet G3 400 MHz/1 MB L2 upgrade (copper) for my Performa 6400 runs between 39 and 49 degrees Celsius. and my Sonnet 300 MHz G3 nubus upgrade (non-copper) for my PPC7100 runs between 49 and 59 degrees Celsius. This is in a non-air conditioned sub-tropical environment and I have had no problems reguarding heat.
That's about it for me!
I hope all is well there with you and yours.
Have a great weekend.
Aloha, Al]

[re: 6400 G3 operating temperatures
I've used a 400mz/512 Sonnet card in my 6400 for about six months. It is also equipped with an ATI graphics PCI card and a USB 2 port PCI card. It is on for an average of 16 hours per day, 7 days per week. It consistently operates at 102° F (39° C) without any problems. By comparison, my D series iMac (333mz) operates at about 95° F (35°C). It would seem that 91° C is high but I have only my own experience to compare.JHG]

[Hi Tom!
I'm writing yo you about the temperature range acceptable for a G3 processor. In all books or articles that I have read, they said that 70 deg Celsius is really ok for a G3. Of course recent Sonnet card made with latest release of the G3 will give you 39 deg in sleep mode and 48 deg in hard works without any added fan in a 6400 (with one pci card installed). I don't know about this specific release of the newer card, but I would not be alarmed by à 70-75 deg. I dont'have an URL or ref to give to you by I'm about 99% sure that the highest temp tolerable for a G3 is about 90 deg Celsius.
Daniel, Canada]

[My 6400/200 runs now at 39 C although I have seen it run warmer, i.e., 42 C and even 58 C. The configuration has a Crescendo L2 400MHz G3 running at 400 MHz with a 40 MHz buss speed and 136 MB RAM, ATI 128 PCI, a QuickDraw accelerator card, 10/100 Fast Ethernet in the COMM slot (w/DSL) and two internal hard drives - I forget how much Gig but a bunch. It's solid.

And here is a letter from a Newer tech L2 G3 who's system crashes when the temps get to high! I haven't heard of this before and wonder if his card is not bad?

How are you ? This issue of temp is very important when it comes to my Newer 300/200/1MB. Never fails, as soon as temp hits 70 -73 degrees room temperature, 6500 power supply fan kicks into overdrive, within 10-15 minutes, machine will lock up. Of course only an issue when G3 is enabled. I have attached extra fans, in top of case which help. But mostly keeping the room temp around 70, ensures reliability. Stays around 68 C. when room temp is 70 degrees F.
I actually put a 486 CPU fan on the G3 heatsink, and screw it in gently to the aluminum heatsink. Helped a little, but removing the subwoofer, and putting 2 Pentium style fans on the top hole (fit fine) of 6500, and top removed. (Machine stays grounded). But G3 temp still needs to be below 73 degrees Celsius, room temp 75 degrees max. Everything is stable, as long as no Audiomedia use, and excess heat.
Apple Authorized Technician]

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This page last updated 8/11/2001