MDD Upgrade/Revival questions

[false_mdd]

Hi! Looks like after all this time my account has finally gotten validated.

TL;DR I bought a dual 867 MDD new when I was a teen and have had it my whole life. This machine is ridiculously sentimental to me, so appreciate the guidance.

I recently completely disassembled it and removed 37 pounds of dust from the internals and am doing upgrades on it. I have a couple sanity questions I'm hopeful for answers to. The end result will be a 4600 TI, SSD, 2GB of new OWC ram for the MDD, atx power supply, cpu upgraded machine. Most of this will be easy, thanks to some of the videos on YouTube from Jeff, Action Retro, etc.

My initial plan was to use the original 133mhz board and install a Dual 1.6ghz Sonnet MDX.

I also have a 167mhz FW400 board and a dual 1.42ghz Apple OEM processor, but no copper heatsink.

Questions:

1) Is the 2mb backside cache on the 1.42 OEM CPU far more valuable than the slight mhz advantage and cooler temperatures of the Sonnet's Freescale chips? I'd have to locate a copper heatsink if so, not the end of the world but am curious.

2) I cannot figure out for the life of me how to get the heatsink off of the Sonnet MDX Duet card to do a repaste. The fan assembly came off easy enough, and I have the necessary bits to remove the screws on the bottom of the card which appear to be holding the heatsink on the pcb but can't get the screws to turn. If anybody has repasted one of these, my google searching so far has turned up nothing.

3) I've not soldered so am hesitant removing the resistor on the 133mhz board to enable 167mhz operation. Similar to the first question, is there tangible benefit from using the 167mhz motherboard (for either CPU I go with) or is there little value in the 33mhz faster bus speed? I have the 133mhz motherboard flashed for the sonnet card and can flash the 167mhz one if needed.

Thanks so much for any advice, thoughts, etc. This MDD is legitimately one of my prized possessions and I've been contemplating recording the entire re-assembly process etc for future help to anybody else since so much of what is out there now is old.

 

[false_mdd]

Here’s the Sonnet card in question. I can’t get the T15 screws on the bottom off. Between the card being old and probably completely crusty paste, and what sort of looks like some uneven paste on it currently, I’d like to put some new Kryonaut or similar paste on.

 

[waynestewart]

I don’t have aftermarket processors for the MDDs but I do for quicksilvers and DAs. I really noticed the difference a larger cache made with those.

To use the 1.42 effectively you either need to change the motherboard or do some resistor changing or it’ll run at 1.1ghz in a 133 bus.
Haven't used 1.42 with an aluminum heat sink but I've used 1.33 with one. That was salvaged from an Xserve.

 

[herd]

Hello and welcome to the forum. It sounds like you have a pretty good grasp of the hardware situation. The various upgrades you mentioned may be quite noticeable, depending on what software you want to run. Some software uses a lot of memory bandwidth, and will benefit from faster bus and larger cache. Other software mainly does better with higher clocks.

You can run the dual 1.42 CPU with one of the other heatsinks, but you may need to add or adjust the fan setup. Mainly, make sure the heatsink is for a dual CPU and has good contact with both silicon dies.

Also, these machines are not very expensive these days. So if yours has particular value to you, it might be easy enough to get a second one to test and experiment on without risking your main machine.

Good luck and let us know how it goes.

 

[false_mdd]

Thank you! I have had a hell of a day today troubleshooting, that’s for sure.

I have four new OWC 2700 dimms replacing my older 2133 ones and thought one was faulty but they all work installed in one particular order, may try to find a PPC memory test or find my old hardware diagnostics cd from the tower.

The aftermarket atx cable or power supply don’t jive with my motherboard. Boots, but fans ramp to 100 and never initializes. Works fine if I plug in the old PSU.

I cannot for the life of me get the sonnet card to install. Patched firmware successfully, but it will not seat properly. No bent pins or anything and putting my 867 in and mounting the heat sink and it boots right up. The mount just does not line up completely accurately, I can always get 3 of four screws but the fourth cannot align, it is marked on the bottom with the sonnet mdx for my MDD and the mounting hardware is correct, it’s just not lining up properly with all four screw holes as it should.

Tried the 1.42 card but my aluminum heat sink for the DP 867 can’t mount on it.

Going to try a spare MDD with dead FireWire tomorrow to see if my mobo is just unique. Good shout that I should have tried all of this on a spare to begin with!

 

[opualuan]

I found a collision with the choke on the dual cpu card and the aluminum heatsink. Find a parts MDD if you can with copper heatsink to use- it works well. Dual processor runs hot, I reverted to single cpu (mild overclock) to keep heat reasonable.

I didn’t have good luck with ATX PSU swap, I ended up having ACX (ebay) recondition the original PSU. Works, but noisy.