The collected works of jc179

Hi all

Ive got a question about over clocking (please read further) the cpu to 200 mhz . I can see it has been done but after checking out a few things I am more confused about what seems to be one small detail.

The german page ( http://hardware.majix.org/computers/sgi ... ning.shtml ) which involves removing & changing two resistors. One of the resistors is replaced with a 4.7 k ohm resistor. The thing which has caused me confusion is while I was reading a post about using a O2 cpu on a indigo2 question, and that answer is isn't possible for a number of reasons, different voltage being one of them, and now Im wondering if its such a good idea... sort of thing

On the german article it reads

" This guide explains how to get a 200MHz CPU Octane R10000 work in an indigo ². This has been done and documented by Andre Schäfer . This has been done and documented by Andre Schaefer. Currently only a german Version is available. Currently only a german version is available."

Which makes me think ok, they are using a Octane cpu module, and the different resistor is to compensate for the voltage difference somewhere (although I don't think the resistor is handling the current, its too small, but thats all speculation.

... It also reads on the next line

Umbau eines Indigo2 R10k/175MHz CPU Moduls zu einem R10k/200MHz Rebuilding an Indigo2 R10k/175MHz CPU module to a R10k/200MHz

Which makes me think were back to using a Indigo2 R10k/175 mhz cpu. So what one are we using ...*hmm*.

On the nekochan.net there is another example of the change, however two resistors are moved from the bottom to the top of the cpu module.

If this is the case and the resistors can be re-used, why did the other site not just re-use them. That's really what i'm wondering.

http://www.nekochan.net/wiki/gallery2/v/SGI_Photos/album56/
see
http://www.nekochan.net/wiki/gallery2/v/SGI_ ... k.jpg.html
and
http://www.nekochan.net/wiki/gallery2/v/SGI_ ... k.jpg.html


Does anyone have any experience doing this? Or insight on anything they have heard but I couldn't find during my searching?

Any info is appreciated

Thanks so much

Jonathan

Hey thanks so much for the reply!

SAQ wrote: I did it. The R10000 processor at 175 and 195MHz uses the same voltage across all platforms. For the modification you use your Indigo2 PMT5, and the only reason you get a Octane or O2 PM10 (or whatever the O2 name for the module is) is as a processor donor for the R10000/200 rated chip. The resistor mod (on your I2 PMT5) changes the clock multiplier to 4x rather than the 175MHz' 3.5x.

Which resistor MOD did you use? I see the two, and still I'm not sure what one is the correct one .... Or are they both the same


So I take it the PMT5 is the sort of cpu board + socket. I'm guessing its possible to setup my 175 to run like a 195 instead of 200 also, if I get the resistor settings for that... ?

SAQ wrote: If you want to risk it, you can even overdrive your existing PMT5's R10000 (they're rated at 180MHz or better) and dispense with the Octane or O2 module altogether.

I don't quite understand what you mean by risk it, are you saying to use the Octane or O2 module (cpu and board) or just cpu ? If I used say a 200 mhz cpu, technically, I wouldn't be over driving anything, and that cpu would go on my pmt5 indigo2 board?

SAQ wrote: R10000 >= 225MHz are a no-go, though, because of the different voltages.

Mine worked just fine for several years, but after that I decided that driving parts beyond their ratings just wasn't worth it for the minor boost it gave. I didn't get the proper 200MHz - rated CPU, though, so it was more of a risk.

Execellent, 200 should be more than enough. Perhaps I can just get a 195 mhz chip and run it at 200 w/o and serious risk. I've done some checking and my 175 mhz cpu @ full load doesn't seem to even get hot to the touch. I think to be safe before I fiddle I will reapply some thermal paste and keep a little monitor handy to keep an eye on it... or just get a 195 if I can find one! , or perhaps even a 200!

SAQ wrote: Anyone here know why SGI tends to underdrive their processors (R10000 at 195MHz rather then the max rating of 200MHz, and I've seen a 4D/35 with a full 40MHz-rated R3000)?

Hopefully someone can shed some light on your question, I really have no idea, unless they felt that 5 mhz under would provide better reliability...

One other question

Does anyone have any info re: what resistors set what multiplier. I ask because If I get a 200 mhz cpu I would like to try to achieve 220, or 225 mhz.

Thanks

Jonathan

Hey all

Just wanted to follow up and firstly say thanks to all who replied! And also give an update on my progress. I decided to try the overclocking method in the nekochan wiki, which was successful 100%. After some more reading I am 99% sure the other article is taking a 200 Mhz from an O2 and using it on the circut board the cpu is fixed to for the indigo2. I think this circut board for anyone else who is/was lost is called / referred to as 'pmt5'. Anyhow it sort of started off to a rough start, as when I tried to remove the two screws on the connector side of the cpu which hold it down in place... well they were um stripped . I tried to remove them carefully but it backed the standoff off the screw on the underside of the motherboard, so this simple procedure turned into an operation. Anyways I removed the standoff's and re- threaded them, as well as the screws. There was enough meat left and I was able to carefully line things up so that I retraced the existing threads and cut a bit of a new one. What an experience, I think a monkey assembled my I2.

Pic of getting ready to fix the screwy screws.

* These may come up slow - be patient its hosted on a computer of the dinosaur era - Ultra1 creator... 167 mhz.

**more are available in the gallery.. ( http://jcbox.dyndns.tv/gallery/I2 )




I proceeded to take apart the cpu module, when splitting it the cpu was attached to the top heat sink - no surprise. I stood the heat sink sideways and gently tapped against the cpu with a plastic poker, it came loose and the heatsink pad was perfectly preserved.

I was able to remove / re solder the resistors no problem, and re assemble the cpu module.

Initially when I powered the system back on, the first thing I noticed was that the system fans were all running faster... not sure if its coincidence or not... So I whipped up a little extra cooling for certain crispy critters. Running the cpu w/o the extra cooling didn't feel hot to the touch, but was certainly warm.

I had to relocate the speaker to install the 2pack of the small fans. Since they are small, and drawing 1.14 a @ 12 volts, you can imagine the annoying jet engine sound they produce when operating, which is why I opted to use 5 volts. I will rig up a small controller to bring them up to 8v or so if things start to get toasty...

pix:


and


Anyways its all working now. I've ordered an O2 200 mhz cpu which I will be installing so if anyone has any picture requests, now is the time to ask!

Jonathan

Hey

I might have left out some info ... I posted late last night sort of a sleep already lol.

cybercow wrote: Congrats!!

- but what you done ? you put O2 200 cpu into I2 module ? right ?

Not yet, it is just the R10K 175 mhz cpu right now. I have ordered a O2 200 mhz R10k cpu from ebay and im waiting for it to arrive. At that point im just going to swap it in... I was just trying to say I think thats what the german page was describing he did. The only part that has me concern'd at the time was the different uses of the resistors... and that perhaps somehow they also changed the voltage signal to the voltage regulator ... but I don't think thats the case...

cybercow wrote: Congrats!!

- i see you are cooling your SI - is that hot ? i wanted to do this with my MXI but there`s no room for any fan ...

cheers

For the fan those aren't that thin (the ones in the picture), but some of the amd (iirc) cpu's had really thin "green" colored plastic fans, mind you they were sleeve bearing, but ok. They were about 3mm thick, which makes them very useful... I can pick them up at the local surplus store here there are boxes of em...

The SI is actually really hot to the touch, I dropped the card down one slot level and made small standoffs from plastic to put in the heatsinks and fan holes to hold it on that angle. I wouldn't say its required, it's just more of my nature to be more safe than sorry... I tend to perhaps over due things a bit P.s. I have since changed my SI for a high impact. . . It doesn't seem to run as hot as the SI... I'm hoping to find a Max Impact then I can keep that cool too!

Same thing with the cpu, with the stock cooler, it wasn't *hot*, but I like to make sure it stays that way...
I think using the 200 mhz cpu instead of the 175 over clocked would also run cooler.

Does anyone have any of the thermal (W) data sheets for these suckers?

Thanks,

Jonathan

jan-jaap

The funny thing is the High impact I have now runs a lot cooler than the SI card... this is of course under load.

I believe you when you say the Max Impact is hot, I bet its incredibly hot !

I'm still trying to find one working or not ... Do you know of anyone who'd have one they would be willing to part with or any defective tram modules ?

cybercow,

The only idea I have is to remove the metal side cover which you pull down to access video cards. That would provide enough room to install a cooling fan. As it is right now you might be able to get in one of those super thin cpu fans and mount them in there. I have one somewhere around here and was contemplating trying it out if I can find it ... If im successful i shall post !

maybe

http://item.express.ebay.com/Computers- ... xpressItem
or similar.

Hey

thanks, thats very good info you have there . I will just keep it at 200 then once I get the 200 mhz chip

Thanks for clearing up the daughter board info as well!

Jonathan

tooR,

this is very cool to see what you've accomplished. Do you have any more details on what you modified on the PMT5 to support the 2.6v / R12k ?

You can use any R12k - 200 mhz upto 300 mhz for this I assume??

Looks pretty zippy running, R12k much faster than the R10k??


Too bad it can't go past 200 mhz!

Good work

Jonathan