MDD 866 Mods

[Protools5LEGuy]

Old article about unleashing the 166 bus on first MDDs
http://www.macbidouille.com/articles/89/page1
http://www.macbidouille.com/news/2002/10/08#3610
http://translate.google.com/translate?u=http%3A%2F%2Fwww.macbidouille.com%2Fniouzcontenu.php%3Fdate%3D2002-10-08%233610+&langpair=fr%7Cen&hl=en&ie=ISO-8859-1&prev=%2Flanguage_tools

Many thanks to Amber's eyes who compared the 2 computers under a magnifying glass for 2h30, Pimus for lending us a brand new G4 Bi-1GHz and Bakayo for his incredible welding skills.
Here are the modifications needed to change the G4 Bi-867's bus clock from 133 to 167MHz.
You'll note that changing the bus speed to 167MHz would overclock the CPU to over 1GHz. To prevent this, you'll have to change the CPU's multiplier coefficient from x6.5 to x6.
WARNING : for your computer to remain stable, you have to use DDR-SDRAM PC2700 modules. The usual PC2100 modules are not certified for working at these kinds of frequencies.

Note that to get the bus from 133 to 166 Mhz, overclockerait machine more than 1 Ghz. To avoid this, you must retake the multiplier of 6.5x to 6x (see this news )
Watch out !!!!!
To ensure the stability of the machine after changes, it is imperative to have only DDR-SDRAM PC 2700! The strips are not recommended 2100 !!!
Changing bus takes 2 steps:
1) changes on the motherboard (the Word is Amber)
the photo is the underside of the motherboard.
I surrounded the three resistors in question.
They are in order R677, R678 and R676

a bus for 133mhz: there is a resistor at each location
for a bus to 167MHz: you must turn in the R676
(It's about 100% on because I had 2:30 to scan both cards under the microscope and that's the only difference)
So there must be other possibilities (I have not taken the time to try and ram no longer lends itself to such practices)

Apple has added a second protection on Bi 867 cards If you just change the settings on the motherboard only does it happen in 167 Mhz on the condition to map a 1Ghz or 1.25 bipro Ghz.
So I'll turn it back to Amber:
So on the map girl pictured, there is a series of three resistors
numbered as follows.
Bus 167 Mhz
R27 nothing
R22 nothing
Resistor R26
Bus 133 Mhz
R27 nothing
Resistor R22
Resistor R26
So it is a security or a lock over Apple

In this screenshot, you see the bus at 167 MHz. The processor board is that of a true dual 1Ghz, not Overclock.

[Protools5LEGuy]

On Mac-Forums one guy make this...
http://www.mac-forums.com/forums/apple-desktops/164289-overclocking-dual-g4-mdd-867mhz-l3-cache-info.html

I have succesfully overclocked Dual G4 867mhz machine by changing the FSB from 133mhz to 166mhz, I removed the two resistors, R676 and R22. I have tested that the machine is stable in Xbench 1.3, Geekbench and in normal usage. G4 chips in my machine are RX933PC so they are rated for 933mhz and now working at 1080mhz.

But, I looked up the Samsung L3 cache chips on my processor card and as far as I know, they are rated for 250mhz (-HC25). L3 cache in MDD models with 1MB of it operate at 4:1 ratio, meaning that the cache in my machine is already operating out of spec, at 270mhz.

Is there any software which I can use to verify the L3 cache speed? Xbench displays incorrect speed, ~4Ghz. I wonder if there is a way to modify L3 cache ratio to 5:1 so I could possibly overclock even further, to 1.25 Ghz? Probably I could just try and see if it can take it, but I would like hear if anyone in here has ever done overclockin for their Dual MDD 867mhz machines and was it how succesful?

[Protools5LEGuy]

Here is the "bible" of MDD cpu modules overclocks
http://web.archive.org/web/20110722181011/http://bitsandpieces.info/Multipliers.htm



This section refers to 1420MHz modules only 

Below is the multiplier table for the 3-Phase LTC3732CG - Note the default voltage for the 1420MHz module is 1.60V

[Protools5LEGuy]

http://xlr8yourmac.com/systems/g4_mirrored_drive_doors/G4_MDD_CPU_Module.html

 Front PLL_CFG array


 Back PLL_CFG array


Voltage regulator

[Protools5LEGuy]

http://translate.google.com/translate?sl=auto&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww.macbidouille.com%2Farticles%2F89%2Fpage2&act=url

Anyone willing to take 133 bus MDD to a higher ground?

[supernova777]

http://translate.google.com/translate?sl=auto&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww.macbidouille.com%2Farticles%2F89%2Fpage2&act=url

Anyone willing to take 133 bus MDD to a higher ground?

i have one.. but im afraid 

after i destroyed my quicksilver 867mhz i am not very brave with hardware mods

[MacTron]

It is more difficult to pass from 166 to 172 Mhz. I've read the instructions once a year since 2003, and I'm still don't know for sure what is the quartz oscillator that must be changed (there isn't even a picture ) and where I can buy it...

[Protools5LEGuy]

i have one.. but im afraid 

after i destroyed my quicksilver 867mhz i am not very brave with hardware mods

To summarize all this post for ours MDD 866 there are 2 things to be done. The board is 133 bus and the cpu is 133bus...

On the motherboard back side

for a bus to 167MHz: you must turn in the R676

And you have a 166 bus MDD board (heaven in OS9 I guess). This needs DDR RAM at 333 instead of 266 (?) so the original memory could not go 333.

You could buy a 166 MDD cpu or  mod the same 866 to be working on 166 bus.

Bus 167 Mhz
R27 nothing, R22 nothing, Resistor R26
Bus 133 Mhz
R27 nothing,Resistor R22, Resistor R26

The thing that everybody talks about is that the 866 at 166 make fail the cache of the cpu,

I have succesfully overclocked Dual G4 867mhz machine by changing the FSB from 133mhz to 166mhz, I removed the two resistors, R676 and R22. I have tested that the machine is stable in Xbench 1.3, Geekbench and in normal usage. G4 chips in my machine are RX933PC so they are rated for 933mhz and now working at 1080mhz.

But, I looked up the Samsung L3 cache chips on my processor card and as far as I know, they are rated for 250mhz (-HC25). L3 cache in MDD models with 1MB of it operate at 4:1 ratio, meaning that the cache in my machine is already operating out of spec, at 270mhz.

and also is recommended to take down the multiplier from 6.5 to 6.

From bits and multipliers...

Step 3.   The table below outlines the PLL_EXT and PLL_CFG[0-3] settings for different bus and CPU speeds. For this example I am starting with a stock 1250MHz speed (7.5x multiplier) setting and upgrading to 1500MHz (9x multiplier) setting. The first number in the fields of the first column represents the PLL_EXT resistor and the following 4 numbers represent PLL_CFG[0], PLL_CFG[1], PLL_CFG[2] and PLL_CFG[3] resistors.

Example: 167MHz system bus and 1250MHz (7.5x multiplier) CPU speed is represented as:

PLL_EXT = 0 (resistor or bridged)

PLL_CFG[0] = 0 (resistor or bridged)

PLL_CFG[1] = 0 (resistor or bridged)

PLL_CFG[2] = 0 (resistor or bridged)

PLL_CFG[3] = 1 (no resistor or open)

Our target speed is 1500MHz (9x multiplier) - This is represented as:

PLL_EXT = 1 (no resistor or open)

PLL_CFG[0] = 0 (resistor or bridged)

PLL_CFG[1] = 1 (no resistor or open)

PLL_CFG[2] = 1 (no resistor or open)

PLL_CFG[3] = 1 (no resistor or open)

There in http://web.archive.org/web/20110722181011/http://bitsandpieces.info/Multipliers.htm is a table that says that our 866 on 166 would be 1083Mhz with
Search for the  "PLL Multiplier Config + Actual Speed on given bus"   table.


Try to buy the smallest soldering iron you can buy. For the JBC solders here in Europe you can find very thin tips for.
We have to be brave to live this era 

[Protools5LEGuy]

It is more difficult to pass from 166 to 172 Mhz. I've read the instructions once a year since 2003, and I'm still don't know for sure what is the quartz oscillator that must be changed (there isn't even a picture ) and where I can buy it...

The instructions from bits and pieces, macbidoule, xlr8yourmac? What is the source of that info?

From bits... there are 3 zones to look out :

 a)PPL CFG (0-3)+ PPL EXT on processor side
 b)PPL CFG (0-3)+ PPL EXT on back side
 c)VID (0-4) on back side



From macbidoule there is also a zone to brake cpu to 133

[Protools5LEGuy]

It is more difficult to pass from 166 to 172 Mhz. I've read the instructions once a year since 2003, and I'm still don't know for sure what is the quartz oscillator that must be changed (there isn't even a picture ) and where I can buy it...

I guess the quartz oscillator is the same than the voltage generator (?), the chip on the VID (0-4). Maybe if you share your quartz oscillator instructions we can find out if it isn`t...

My references are here in this post ALL. Any more info, please, share here.

Is there any technician with skills to pull out the RAM of the CACHE of the cpu daughterboard and change it? Maybe is easier that what we thought to go 2 Mb cache.
In the

On Mac-Forums one guy make this...
http://www.mac-forums.com/forums/apple-desktops/164289-overclocking-dual-g4-mdd-867mhz-l3-cache-info.html

I have succesfully overclocked Dual G4 867mhz machine by changing the FSB from 133mhz to 166mhz, I removed the two resistors, R676 and R22. I have tested that the machine is stable in Xbench 1.3, Geekbench and in normal usage. G4 chips in my machine are RX933PC so they are rated for 933mhz and now working at 1080mhz.

But, I looked up the Samsung L3 cache chips on my processor card and as far as I know, they are rated for 250mhz (-HC25). L3 cache in MDD models with 1MB of it operate at 4:1 ratio, meaning that the cache in my machine is already operating out of spec, at 270mhz.

Is there any software which I can use to verify the L3 cache speed? Xbench displays incorrect speed, ~4Ghz. I wonder if there is a way to modify L3 cache ratio to 5:1 so I could possibly overclock even further, to 1.25 Ghz? Probably I could just try and see if it can take it, but I would like hear if anyone in here has ever done overclockin for their Dual MDD 867mhz machines and was it how succesful?

 

there are references about the 1Mb cache of the 866 dual, limited to 250 MHz operating at 4:1 ratio working out of specs... What Samsung cache chips take the 1.42, 1.33 and 1.25 "golden duals". Is out there ANY reference of swaping the cache chips? 

[supernova777]

from what i have read about pc overclocking..
this is totally possible
that the cache memory cannot reach the proper speed
this is oftenthe biggest factor in overclocking
which is why pc overclockers always always want the craziest fast
ram so they can achieve higher multipler
so it makes sense that the cache ram is whats holding it back

plus.. i also read that the quicksilver 733mhz cpu is very popular for overclocking
because it lacks the cache ram entirely.. and therefore it can be overclocked to 933mhz
very easily!

https://translate.google.com/translate?sl=fr&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=https%3A%2F%2Fsites.google.com%2Fsite%2Foverclockmac%2F&edit-text=&act=url
https://translate.google.com/translate?sl=fr&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=https%3A%2F%2Fsites.google.com%2Fsite%2Foverclockmac%2F&edit-text=&act=url

as we can see in the attach document changing a 733 qs cpu is the only overclock for mac
that u can do by cutting a single trace to a resistor going from 733 to 800
or by moving the resistor u can make it a 867  or a 1067
to make it a 933 or 1000 u need an extra resistor from some place to add
this seems like the best option to get a 1ghz single cpu quicksilver!!

[Protools5LEGuy]

from what i have read about pc overclocking..
this is totally possible

https://translate.google.com/translate?sl=fr&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=https%3A%2F%2Fsites.google.com%2Fsite%2Foverclockmac%2F&edit-text=&act=url

Thanks for the link!
Someone tried too to put in order the bits article
https://translate.googleusercontent.com/translate_c?act=url&depth=1&hl=en&ie=UTF8&prev=_t&rurl=translate.google.com&sl=fr&tl=en&u=https://sites.google.com/site/overclockmac/g4mdd&usg=ALkJrhj7-0rGMVdKifn347AFqLocMO3unQ
At least I can copy that table from there...

!!! Warning !!!

The presence of a resistance equivalent to a "0" in this table and the lack of resistance to "1

[supernova777]

im reading here.. that its possible to take a sawtooth to  133mhz bus by openfirmware only???
am i reading right?

http://www.xlr8yourmac.com/G4ZONE/sawtooth/SawtoothCPUdesign.html

as long as u have pc133 ram..and mac os 9.1+
+ openfirmware hack
= 600mhz g4 from a 450mhz

[Protools5LEGuy]

https://translate.google.com/translate?sl=fr&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=https%3A%2F%2Fsites.google.com%2Fsite%2Foverclockmac%2F&edit-text=&act=url
https://translate.google.com/translate?sl=fr&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=https%3A%2F%2Fsites.google.com%2Fsite%2Foverclockmac%2F&edit-text=&act=url

as we can see in the attach document changing a 733 qs cpu is the only overclock for mac
that u can do by cutting a single trace to a resistor going from 733 to 800
or by moving the resistor u can make it a 867  or a 1067
to make it a 933 or 1000 u need an extra resistor from some place to add
this seems like the best option to get a 1ghz single cpu quicksilver!!

Taking the MDD866 dual to 10xxMHz is just pull off two resistors too...

The QS 733 chip even overclocked to 1067 should be "slower" than a DA 733 due to the 2Mb cache...

What about to "exchange" the cache chips? It is micro tech, not nano tech.  Any TV Service repair shop should have the electric soldering iron to desolder the cache...What is unknown is if the "new" cache would be a waste of time and money. Maybe not all cpu daugtherboard can take advantage of the chips installed. Some cpus work despite having the cache out of specs/broken

[MacTron]

im reading here.. that its possible to take a sawtooth to  133mhz bus by openfirmware only???

no.

am i reading right?

http://www.xlr8yourmac.com/G4ZONE/sawtooth/SawtoothCPUdesign.html

as long as u have pc133 ram..and mac os 9.1+
+ openfirmware hack
= 600mhz g4 from a 450mhz

this CPU at 600MHz will not even boot.

[MacTron]

Of course the cache chips can be changed, even the G4 chips... it cost between 100 and 200 EUR. But why? I have not ever found a synthetic or real test that shows some benefice of 2MB of L3 against 1MB of L3. My last try was with the xServe CPU...

[MacTron]

I've pushed a [email protected] dual module up to 1.750 in to a MDD. It was the last time I felt a computer FAST: Pure speed.

[MacTron]

I've overclocked some PC also, the basis are the same, but very different CPUs and motherboards, so it is different technic.

[Protools5LEGuy]

Of course the cache chips can be changed, even the G4 chips... it cost between 100 and 200 EUR. But why? I have not ever found a synthetic or real test that shows some benefice of 2MB of L3 against 1MB of L3. My last try was with the xServe CPU...

BUT Real World tests and DAW uses show that a 2Mb of L3 make the CPU to have more inertia, more power. I guess this is mainly because in a CPU cycle the CPU can see 1 or 2 Mb. On x86 computer is clear that a CPU with more cache is more "powerful". Maybe the synthetic tests you have made are simply not aware of this. I thought cinebench would...

The geekbench test is well know that has nothing to see with the real world tests.


Final Cut Pro 3.0 test the system in the first run to know how many video layers/ rtime effects can be run at the same time. (Yes, I know it can be hacked) ... http://www.xlr8yourmac.com/tips/final_cut_pro_3_tweaks/final_cut_pro_3_tweaks.html

Logic >4 take advantage of the 2nd processor and the Altivec if found.

Chris had come with the perfect example. Compare the DA 733 with the QS 733 performance with cinebench or geekbench or OS9benchwhateveriscalled.

[supernova777]

in most of your mdd overclocks u are probably using pc3200 ddr 400 ram right?
the machines were originally made for pc2100 ddr266 or pc2700 ddr-333 ram
(2100 for the first mdds i beleive)
which is why using pc3200 ram allows the cpu to go higher..
u have this room for overclocking to be successfull ..
because the ram can match the increased frequency

on a g4 if u use pc100 ram.. theres no way overclock is gonna work
people who have shitty ram and try overclocking will fail

well really its not that the ram is shit.. it just isnt rated high enough to match the territory
that u push teh cpu to.. its "off the map" of what it can do