O2 250MHz R10K Modded/Overclocked to a 350MHz R12K

[konon007]

Have you restored the pictures for modding O2 and Octane CPU modules on the server?

[konon007]

Help, guys!

Chicago-joe doesn't respond.
As I remeber, many nekochaners played with O2 and Octane CPUs modding several years ago. So, they maybe have these pictures....So, please, post somewhere or send me to mailto:konon@yandex.ru the pictures of R10/R12k CPU modules for O2 and Octane that show what resistors I need to move to change the frequency multiplication ratio!!!

Many thanks in advance!

Regards,
Oleg

[rumble]

Chicago-joe doesn't respond.

Has anybody heard from Joe? I PM'd him a few months ago regarding his RM7900 upgrade, but it doesn't look like he's even seen it yet.

[BrentDMartin]

Oleg

I think you're the guy who recently outbid me on ebay at the last second for an O2 300 MHz R5000 system!!!

I remember the bidder was listed as being from the Russian Republic, if I recall correctly.

That was my first time ever bidding on an O2! I was so surprised to have it snatched away from me at the last moment of the bidding process. I've gotten smarter about bidding since then!!

No hard feelings, though.

Since then I've gotten two more O2s, but not a 300 MHz R5K one.

Good luck with your overclocking!!

Brent

[Dr. Dave]

If I can find my modded CPU board, I'll try to figure out what was changed and snap some new photos. A cursory glance last night revealed I haven't looked for it in a while - I ended up with a 400 MHz R12k PM and have been using the old one since, and I think I baked it during testing. Doesn't change the resistor settings though.

[konon007]

So, anybody cannot find or make the pictures?
Where have you gone, sgi overclockers?....

[NeZetiC]

I don't know if konon007 had an answer during this 3 weeks, but today, I have got the same problem.

I want to upgrade my R10K 225 O2 with an R12K 300 CPU module.

But joe have modded a 250 to 300 and there is today no pictures to give me clues.

joe had a 250 R10K, with 100 Mhz oscillator. Stock CPU board got a 2.5 multiplier : 2.5 x 100 = 250 Mhz Ok, I agree.

I have a 225 R10K. But first, I don't know oscillator frequency. I think it's something like 90 Mhz, because for exemple : 90 x 2.5 = 225, 90x3 = 270, and this the value I want to have (I dont want to change oscillator, and R12K 270 Mhz is enough for me).

So reading and folowing joe indications (viewtopic.php?t=1230&start=0), I've try to search resistors that make a multiplier of 2.5 (0100 if I read the table of binary string to clock mutiplier).

I found something interesting on CPU board that can be what joe speak about in his post.

I made some pictures with indications :

The board
Resistors

I have columns of resistors, with a resistor on the bottom or on the top (so 0 and 1 value ?). If I read from column 9 (bit 9 ? ) to column 12, I have my 0100 value.

But all this is just suppositions, if someone could post on this forum old joe pictures or his own modifications, or just tell me what he did with his CPU board, if I'm totaly wrong or not, that would be great

[konon007]

Hi NeZetiC,

Unfortunatelly, I didn't received any pictures from that time - very strabge that anybondy had that old pictures...

I hope to get R12k 300Mhz O2 soon and will compare its CPU to R10k 250Mhz O2 CPU to identify which resistors I have to move.

[NeZetiC]

Code: Select all

CPU: MIPS R12000 Processor Chip Revision: 2.3
FPU: MIPS R12010 Floating Point Chip Revision: 0.0
1 270 MHZ IP32 Processor
Main memory size: 256 Mbytes
Secondary unified instruction/data cache size: 1 Mbyte on Processor 0
Instruction cache size: 32 Kbytes
Data cache size: 32 Kbytes
FLASH PROM version 4.18
Integral SCSI controller 0: Version ADAPTEC 7880
  Disk drive: unit 2 on SCSI controller 0 (unit 2)
  CDROM: unit 4 on SCSI controller 0
Integral SCSI controller 1: Version ADAPTEC 7880
On-board serial ports: tty1
On-board serial ports: tty2
On-board EPP/ECP parallel port
CRM graphics installed
Integral Ethernet: ec0, version 1
Iris Audio Processor: version A3 revision 0
  PCI Adapter ID (vendor 0x9004, device 0x8078) PCI slot 1
  PCI Adapter ID (vendor 0x9004, device 0x8078) PCI slot 2
Video: MVP unit 0 version 1.4
AV: AV1 Card version 1, Camera not connected.
Vice: TRE


And it's a success

Like nobody have been able to give me a help, I decided to try the tip with all informations of all posts I read on Nekochan and my personal reflections.

My first idea was not so wrong, it's the good part of CPU board, but not the good resistors (not at all).

I post as soon as possible photos and some explanations how to mod from R10K225 to R12K270 (or to R10K250 to R12K300, it's the same thing).

Now, I also found informations (from joe) about a tips to over clock the oscillator, from 90 to 100 Mhz, to allow my R12K300 to run at full speed, but I can't find resistors on the board (it's more difficult than the first manipulation).

I think that a High Res picture from the bottom of a R12K300 board would be great to find them, so if you can

An article on nekochan wiki about that too...

[NeZetiC]

Ok, I don't understand how to change oscillator frequency...

But I can post how to overclock the CPU.

If you have R10K225 or R10k250, it's the same thing, you must change multiplicator from 2.5 to 3.

After that, frequency will be changed from 225 Mhz to 270 Mhz or from 250 Mhz to 300 Mhz.

So, to mod an O2 from R10K to R12K, you must :

- Have an Octane R12K300 CPU module (or a R12K processor alone, why not).
- Swap processors (be carefull when you remove radiators)
- Move two resistors

The Board and area where are this two resistors

And this is the resistors I moved :

R537 -> R538
R552 -> R553

Code: Select all

O2 R10K 225 Mhz :
R508
           R510
R514
           R517
           R523
           R530
R534
           R537
R540
           R541
R544
R547
           R548
           R550
           R552
           R554
           R556
R559


Code: Select all

R12K 270 Mhz :
R508
           R510
R514
           R517
           R523
           R530
R534
R538
R540
           R541
R544
R547
           R548
           R550
R553
           R554
           R556
R559

The most important thing, as joe said : be carefull with static shocks ! CPU modules are extremely fragile.

And move resistors require some skills, it's tiny chips (2mm).

Have a fun with your O2

(I search more ram for it, if you have, PM me )

PS : I'm not responsible if you damage your system. This worked for me, but there's no warranty.

[NeZetiC]

Code: Select all

CPU: MIPS R12000 Processor Chip Revision: 2.3
FPU: MIPS R12010 Floating Point Chip Revision: 0.0
1 300 MHZ IP32 Processor
Main memory size: 1024 Mbytes
Secondary unified instruction/data cache size: 1 Mbyte on Processor 0
Instruction cache size: 32 Kbytes
Data cache size: 32 Kbytes
FLASH PROM version 4.18
Integral SCSI controller 0: Version ADAPTEC 7880
  Disk drive: unit 2 on SCSI controller 0 (unit 2)
  CDROM: unit 4 on SCSI controller 0
Integral SCSI controller 1: Version ADAPTEC 7880
On-board serial ports: tty1
On-board serial ports: tty2
On-board EPP/ECP parallel port
CRM graphics installed
Integral Ethernet: ec0, version 1
Iris Audio Processor: version A3 revision 0
  PCI Adapter ID (vendor 0x9004, device 0x8078) PCI slot 1
  PCI Adapter ID (vendor 0x9004, device 0x8078) PCI slot 2
Video: MVP unit 0 version 1.4
AV: AV1 Card version 1, Camera not connected.
Vice: TRE

With pictures of an R12K300 CPU board, taken by a friend, I've been able to overclock the SysClock from 90 Mhz to 100 Mhz.

Now my O2 run at 300 Mhz, with 1 Go of Ram lent by another friend

From R10K225 Mhz to R12K300 Mhz, so cool

Joe, if you read this one day, you're my hero

[NeZetiC]

Some news about my R10K225 to R12K300 mod. My O2 continues working very well

I have made a schematic with the picture of R12K300 CPU board (bottom side) to indicate resistors you must move to overclock the Sysclock from 90 Mhz to 100 Mhz (and so overclock CPU from R12K270 to R12K300, or from R10K225 to R10K250 if you don't have R12K chip).

You can find it on my website : www.nezetic.info

Good luck if you want to try this.

Again be carefull with static shocks !

Just for fun (I don't have R10K225 scores, sorry...) :

Before

Code: Select all

CPU: MIPS R12000 270 MHZ
Dhrystones : VAX MIPS rating =    531.703
Linpack : Unrolled Double  Precision 110062 Kflops
Whetstone : MWIPS    656.867

After

Code: Select all

CPU: MIPS R12000 300 MHZ
Dhrystones : VAX MIPS rating =    594.373
Linpack : Unrolled Double  Precision 120207 Kflops
Whetstone : MWIPS  732.340

My first CM

Code: Select all

CPU: MIPS R5000 300 MHZ
Dhrystones : VAX MIPS rating =    379.343
Linpack : Unrolled Double  Precision 44572 Kflops
Whetstone : MWIPS  392.908

Pretty cool

[RandomDamage]

Excellent! Thanks for documenting this. I'll try the mods this weekend. (I already have the CPU multiplier changed to 3x)

[RandomDamage]

Did the resistor change yesterday and everything seems to be working just fine at 300MHz. I ran it overnight just to be sure. The R12K CPU is rated for 300MHz so I would have been surprised if it didn't work. My R10K 225MHz O2 is now a R12K 300MHz. Cool!

[NeZetiC]

Congratulation RandomDamage !

I'm happy to see that my work can help other people.

I've another friend that want to do this mod. I wanna see more DIY R12K300 O2

So if you do it successfully, don't forget to post here.