Overclocking a Sonnet Encore MDX

[Knez]

Hi!

Me and a friend have a bit of a project lined up and for that we need some close up's of the back of a Sonnet Encore MDX 1.8ghz.

We are trying to see if it's possible to overclock the 1.6ghz version, so we need pictures of the 1.8ghz version to have something to compare the 1.6 against.

Hopefully we'll find where to change the multiplier and voltage.

So if someone here has a 1.8ghz MDX and feels like taking some pictures of it, please do and post them here in this thread

 

[asaggynoodle]

This should give you a good start, I just threw this together. Let me know if something is not making sense or any errors, I can go into depth.

While the Diagram is not the Upgrade card you have, the configuration jumpers *Should* still represent the Pattern "10101" Unless Sonnet moved them around (It happens). Also, they usually will be grouped together very relatively close to the CPU as per stock Apple boards if you don't know where they are. 

IF you could post a picture of the back of your MDX I'd be able to point out which ones are which.

*Edit, Just looked at the Datasheet for the MDX's, they are the same physical boards. So they WILL one way or another be overclockable via jumpers as sonnet isn't going to make a custom revision for each speed part.

 

[Knez]

A picture of the back of the 1.6ghz MDX is attached to this post

 

[Knez]

Took a picture of the front of the card as well while I had it out of the MDD.

On a side note; the stock aluminium apple heatsink fits perfectly over the MDX CPU board.

Just switching the heatsinks lowered it's idle temperature with ~5C.

 

[asaggynoodle]

So some good news and bad news (I Guess)..
I don't know which ones are which, the Voltage controller is easy, as it's that LTC chip on the top side. So if you're content, you can modify the voltage no problem.
Page 17 of http://cds.linear.com/docs/en/datasheet/170989f.pdf shows the direct Pin to Configuration controls. Easy as cake there, just pull VID pins 1-4 either to Vcc or GND in accordance to that Datasheet config.

The Multiplier Resistors are who knows where. IF I had to guess (And they were there) I'd be thinking they are on the top right side of the card. But since they look scrambled from what I can tell who knows.

THERE IS HOPE. I know you're going to think I'm crazy here, but all of the VIA's for each Chip are located at the bottom. So basically, if we look at the Datasheet and figure out the pin out of the BGA, we can see which pins are the PLLCFG pins to bypass the resistors all together. Then all you have to do, is solder a fine jumping wire directly to the Vias on the bottom of the BGA to the GND/Vcc in accordance with the PLL you want. If you're good at soldering, you should be okay.

Here I just did all that for you lol. 

Looks like you'd only have to jump two pins, as the rest stay the same in the config. Only Purple and Brown are going to change to get 1.8Ghz. 

Purple gets pulled down to GND.

Brown will get pulled up to Logic High/Vcc. 

 

[Knez]

Great! I'd still like to find where the actual PLL resistors are. Im interested to find out where the limit is for the 1.6ghz MDX

What's the best way forward?

 

[asaggynoodle]

The thing is we don't know how the configuration is laid out in 3rd party boards. There is really no way of knowing exactly. 

From all the Datasheets I have, the CPUPLLCFG resistors are all rated as 10K, or in SMD case, "103". So, your best bet is to look for any resistors the have "103" on them. Then we can go from there.

 

[Knez]

I just got my hands on pictures of the 1.8ghz model. Attached them to this post.

I haven't had time to sit down and compare the boards myself, but now it's at least possible to do just that.

EDIT: Just compared them briefly and they look identical to me.

 

[Knez]

So I actually found where some kind of multiplier setting it. I tried 1.8ghz but only got a chime and black screen at boot.

So I ended up going from 9.5x (1.58ghz) to 10x (1.67ghz) and it's rock solid. Too bad I can't seem to figure out how to set the multiplier to 10.5x so I can try reaching 1.75ghz.

This thread might be better off in the hacks and mods forum when I think about it.

 

[Bunsen]

Moved.

Would you like me to change the title as well?  Something like "Overclocking a Sonnet Encore MDX"?

 

[Knez]

Sounds good!

 

[Bunsen]

Done