LC630 overclocking 33->40MHz success

[Brett B.]

Just did the resistor swap in my LC630 tonight to bump it up to 40MHz. I do have a real 33MHz 68040 chip and a heatsink that I stole from a Q700.

Successful results, OS 8.1 is a LOT more snappy. Significantly better video performance. Dark Forces is actually playable in full screen! I shoulda done the mod years ago but this is THE single most finicky computer I've ever owned...so... I was a little skeered.

Speedometer before/after results:

CPU............1.13.......1.41

Graphics.......1.05.......1.33

Disk............2.71.......2.81

Math...........19.23......23.88

P/R.............1.39.......1.71

:rambo:

 

[uniserver]

awesome



maybe get a fan on it and push it to 48, 50?

 

[Brett B.]

I'm not sure how much more I want to push it, for ONE reason - my DOS card covers the video chip on the logic board. This isn't such a bad thing for the CPU, though, since it moves the '040 chip up about half an inch and back about 2" so it's directly under the fan. There's just no way to get airflow to the video chip and it'd be a bummer to burn it up, since the LC630 DOS compatible machines used a slightly different logic board and I'd never find another one.

 

[Byrd]

I've had the same setup - DOS card LC630 @ 40Mhz full '040, no issues for years, just put a thin 486-size heatsink on it.

 

[TheEisenfaust]

I wish I had a PC compatibility card for my Macs... Lucky. :lc:

 

[Byrd]

The DOS compatibilty card in the 630 is quite a strange looking beast, it kind of reminds me of some of the upgrades for Amiga hardware - piggybacked on top of things and looks kind of unruly. It is however a great card, the CPU is socketable and I was rocking a 5x86-133Mhz in there for a while (Windows didn't work with it though, limitation of the BIOS with an "unknown" CPU), now a Intel Overdrive 486DX4-100 works properly in there now.

 

[Brett B.]

I wish I had a PC compatibility card for my Macs... Lucky. :lc:

If you have a 6100, I have a NIB (but opened) Apple brand DOS card that I might part ways with.

They are definitely interesting things, I was lucky enough that my LC630 was my first Mac, and is probably my most unique and definitely my favorite.

 

[TheEisenfaust]

Well, I'm at work right now so I don't remember my whole collection atm. For sure though I don't have a 6100. This is what I have:

Apple IIGS

Macintosh SE

Performa 450

Performa 631CD

LC 575

Power Macintosh 6500 W/ Sonnet G3 upgrade

Power Macintosh 7600 (or was it 7200...)

Power Macintosh 8600 (or was it 8500...)

Power Macintosh G3

Power Macintosh G3 B&W

Power Macintosh G5

And that's it for my desktop models. Any chance your card could fit in one of those?

 

[coius]

Most likely the Performa 631CD is your best bet. That's pretty close. It should fit into the CPU socket

 

[coius]

Oops disregard that. The 6100 is a power mac and I believe uses Nubus for the PC Compatibility card (or rather the PDS I think. I can't remember if the 6100 replaced the 610's PDS with NuBus and right-angle adapter. All I had was the Centris 610 a long time ago)

 

[Brett B.]

Yup you're out of luck there, at least with the machines you've got. You can get one for your 631CD, although they are kinda hard to find. My LC630 came with one from the factory.

 

[TheEisenfaust]

Lol Just my luck... xx( Well I guess I just need to liberate a compatible Macintosh from oppression to get a Compatibility Card! :rambo: And the hunt continues.