The 1.6ghz Sonnet Encore MDX overclocking project

[Knezzen]

I recently stumbled upon a 1.6ghz Sonnet Encore/MDX Duet upgrade for the MDD and XServe G4 and I couldn't really keep myself from buying it. The whole reason for the purchase was to see if the 1.8ghz version shares CPU with the 1.6ghz model with just the core multiplier crippling it. A nice overclocking project!

I contacted MacTron and got to work with taking pictures of the front and back of the MDX.
MacTron made some discoveries and.... we got stuck. We need to find the core multiplier resistors, and since the documentation for the MDX board is internal for Sonnet, we don't have any documentation to help us do so.

So now we need your help!
Do any of you guys own a 1.8ghz MDX and feel confident enough to remove the heatsink and take some pictures of it?
Pretty much the only thing we can do now is try to find some high resolution pictures of the 1.8ghz MDX board and compare it to the 1.6ghz I have.

Please help us help you!
If we manage to get the 1.6ghz stable at 1.8ghz or above, we have a pretty cheap upgrade path for those of us who need even more power than a overclocked 1.25ghz MDD CPU can manage, or just because we want more power


I have attached the pictures I have taken of my 1.6ghz board to this post for archiving purposes.

[devils_advisor]

run down the components and start ruling out

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwi9-KCAlu3PAhWM4SYKHSMJBZEQjRwIBw&url=http%3A%2F%2Fwww.kynix.com%2FDetail%2F169415%2F1888174-6.htm&psig=AFQjCNE_JLpJxZRv-IqG1BOssbe39tawRg&ust=1477183069897919

http://www.digikey.com/product-detail/en/linear-technology/LTC1709EG-9-PBF/LTC1709EG-9-PBF-ND/963586

eventually you can narrow it dow to an area of the board

[MacTron]

The LTC1709 chip is the Voltage Regulator.

[Knezzen]

Bumping this thread a bit. We still need your help!

Do anyone here have a 1.8ghz MDX and want to contribute with some pictures of it? It would really help alot!

[GaryN]

Here you go Knez.
Have fun overclocking your practically-irreplaceable upgrade board.
Just don't let the smoke out.

I notice we both took pix before wiping the goo off of the CPUs d-oh
Mine are 7447B's

Interesting side note: After reassembling with fresh Arctic Silver, the CPU temp dropped 3 - really - 3 degrees C!

[Knezzen]

Thanks Gary! Now we can keep on going

EDIT: Just compared them briefly and they seem identical to me
MacTron: Do you see any difference between the two? I might have missed something.

EDIT AGAIN: The model number on the CPU's seems to be identical as well, which is good at least; 18ARE10516D001.

[MacTron]

MacTron: Do you see any difference between the two? I might have missed something.

OK, I'll take a look.

[MacTron]

I got something :




But the resistors 102 do not match as expected.

[Knezzen]

I wonder where the rest of the resistors are... hum.

EDIT: MacTron, I see an error in your picture there. The 1.6ghz MDX actually runs at 1.58ghz and not 1.67ghz, so it should be running with a 9.5x multiplier and not 10x like in your picture.

[MacTron]

EDIT: MacTron, I see an error in your picture there. The 1.6ghz MDX actually runs at 1.58ghz and not 1.67ghz, so it should be running with a 9.5x multiplier and not 10x like in your picture.

... so my theory is invalid.

Anyway, the only difference I have found was those resistors, so changing them will convert a 1.6 card into a 1.8 card or not! 
... this is a risky business...

[Knezzen]

Anyway, the only difference I have found was those resistors, so changing them will convert a 1.6 card into a 1.8 card or not! 
... this is a risky business...

So should we find out? Im only 100 euro out of pocket and if only the one resistor is the key, then the odds of finding a 1.8ghz MDX suddenly got doubled if you are willing to do a quick solder.

I'll double check the boards before I do anything, could you as well MacTron? Just to be 100% sure that this is the only difference.

[MacTron]

I'll double check the boards before I do anything, could you as well MacTron? Just to be 100% sure that this is the only difference.

I have double checked the pictures, and the only physical differences are those two resistors.

But I think that we have to wait, there is some weird things that need to be answered. May be someone know the answers.

# why both cards seems to work at the same voltage ?
# the upper rigth componnet of the card (C&K BPA02) is a DIP swich?
# can be the bus multiplier and the core voltage be set by some kind of card firmware?

[Knezzen]

# why both cards seems to work at the same voltage ?
# the upper rigth componnet of the card (C&K BPA02) is a DIP swich?
# can be the bus multiplier and the core voltage be set by some kind of card firmware?

About the DIP switch. Found this in the official install PDF for the MDX.


Found this text about the Sonnet Encore/ST 1.7ghz on everymac.com:

The Sonnet Encore/ST G4 1.7 features a 1.7 GHz MHz PowerPC 74xx (G4) processor with the AltiVec "Velocity Engine" vector processing unit and a 512k level 2 on-chip cache.

The card plugs into the G4 daughtercard slot provided by the AGP-based Power Macintosh G4 models (AGP, Gigabit, Digital Audio, Quicksilver 2001/2002, and a separate version for the Cube), replacing the original processor card.

All Encore/ST models utilize Sonnet's unique "AutoConfigure" technology to automatically detect what computer is being used and set the speed to the maximum safe setting.

Compatible with MacOS X 10.3.5 and higher, but requires MacOS 9.2 to install a provided firmware patch.

The MDX most certainly uses the same mechanism to set the multiplier and voltage.
Perhaps the changed resistor is the "switch" between 1.6ghz and 1.8ghz to some kind of control chip that sets the voltage and multiplier accordingly?

[Knezzen]

So success! Almost... I went ahead and soldered on the card. Soldering it like Garys 1.8ghz card gave me a boot chime but a black screen... No success. I tried another approach. I bridged both R103 and R104 and success! The MDD booted, but I only got dual 1.42ghz CPU's now.



So it's more or less certain that the 1.58ghz Sonnet wont do 1.8ghz, at least not mine.
Now to see where the limit is. 1.67ghz would be nice at least, or perhaps a bit more


EDIT:
I reached 1.67ghz! And it's very stable. Removing R104 and R105 and keeping R103 in place equals 1.67ghz.
Since I'm not able to do 1.8ghz the only thing left is to find the 10.5x multiplier which would give me 1.75ghz.
If this doesn't work I still have 1.67ghz which I'm more than satisfied with. And it's 1.67ghz running very cool.



Right now it's at 36C with the aluminium heatsink from my overclocked dual 1.25ghz module with 3 tabs open in TenFourFox and Spotify playing in the background. Adding some high quality thermal paste and a copper heatsink would make for a very cool running and stable machine.

[MacTron]

Awesome!
Great Job!
 

[MacTron]

BTW, what resistors configuration would give you 1.75ghz. ?

[Knezzen]

BTW, what resistors configuration would give you 1.75ghz. ?

I have no idea actually. I bought some Arctic Silver 5 today, so I'm giving it a go after dinner tonight. If you look at the picture of the front of the card there is a chip with a sticker with "XG4B". All the resistors I have messed with does to this chip one way or the other.

This chip must be the "automatic configuration" that Sonnet uses on their G4 upgrade card.
You probably set it with the resistors to your wanted frequency and the chip sets the multiplier and voltage accordingly. This is just a theory of mine, but is seems plausable.

[Knezzen]

So it's more or less certain that the 1.58ghz Sonnet wont do 1.8ghz, at least not mine.
Now to see where the limit is. 1.67ghz would be nice at least, or perhaps a bit more

I'll take that back now

[GaryN]

So, what did you do?

[mrhappy]

So, what did you do?

Something very cool!!! Nice work Knezz!!