Overclocking *SGI*SUN*MIPS*SPARC* RISC!!!

[Toaster]

Hi folks!
Ah my new love..RISC!
Very recently, I decided to delve into overclocking the MIPS and SPARC CPUs and thier associated busses. Remember, these fine CPUs are delegated to Silicon Graphics and SUN Microsystems based systems. DO NOT assume this was done with X86 based equipment, only RISC.
So far, I cranked a MIPS R5000, R4400, R4600 and soon...a R10K CPU/s used in SGI equipment.
The R5000 seems to be the easiest to crank as the base unit I used was a 200mhz 512KB cache unit. It now, zips merrily along at 275mhz and faster crystals are in the mail for 300 and 350mhz.
The MIPS 4x00 CPUs are all "SC" units of 1024KB cache or more.
One particular unit, a R4400/SC boasts 2048KB of cache now running at 250mhz from its 150mhz rating.
On to the SPARCS!
First unit was a ROSS/166 mhz unit in a SUN SS/20. It topped out at about 200mhz and this particular system can handle 4 of these babies!
If you havn`t messed with an SGI or a SUN, you are missing out!
Soon, most of my X86 stuff will be off to EBAY or available here in the for sale forum.
Bless me Intel, for I have sinned...and I shall again...and again...and again.

As a side note, I have 2 big builds/installs coming up. The equipment has been delivered, reservations set for transportation and all we wait for is the final shipment of equipment. I`ll be away for about 2 worj=king weeks and i`m sure you folks will behave yourselves. If not, I`ll tell Santa`s reindeer and Santa himself to take a narly dump down your chimney!

[DrZaius]

Toaster, can you please give a brief overview of these processors? I've seen them mentioned before (SPARC, RISC, etc.) but I don't really know what they are. How are they, at speeds of 200MHz and such, compared to x86 processors? What are crystals? I'd really like to learn more. Thanks.

[Hpro]

Hi,
use the link below to read about RISC technology - need to read it all and can be somehow confusing..

RISC

BTW, intel processors also include RISC Instruction sets and the gap between CISC and RISC becomes form day to day less..

Than main feature on RISC is may the linear Memory addressment - not like in the X86 where you will have the VGA memory address stealing it's place right at the beginning of the the aligned memory (C000:0) address for the VGA

SPARK, ALPHA etc are High Grade High end processors all using RISC as I know..

CRYSTAL is the TIMEGIVING TOOL together with the PLL (Phase Lock Loop ) of the CLOCK GENERTOR CHIP on the MOBO for the regular Motherboard of the X86 line this will be 14,31818MHz .. This frequency will be mutliplied to 33Mhz for the PCI Bus and it will be multiplied to 66Mhz for the Pentium and Celeron Bus (there is also the possibility to let it run at speeds of 50 55 60 Mhz ) this for all CPU's which wouldn't run faster than 233MHz..

Then also it gives the exact time for the TIMER (System Time 32.786Khz)and also the needet 24Mhz for the Floppy drive and 8-16 Mhz for keyboards use..

I suppose because of the reason that those MOBOS Toaster used can't be overclocked by just setting the MULTIPLIER Jumper to a higher level so what he has done is that he changed the STARTING Frequency (Can't tell you how much this is on the RISC)say from 14.318 say to 18 Mhz this then would equal a increase in the System Bus speed..
Calculations beneath..

Say the Jumperset on the MOBO is set to 60MHz then changing the CRYSTAL OSCILATOR to 18 MHz instead of the Original 14,31818MHz multiplied by 60 would give you a BUS SPEED of 75,43 MHz multiplied by 4X (jumperset) will equal 300MHZ CPU speed instead of Only 240..

the same counts for 66Mhz..
18/14.31818*66=82.97Mhz * 4 = ~ 332Mhz

There is more to change because this changes also will influence the System Clock and the Floppy controller and the PCI BUS - the floppy will stop to read or write and System Clock will beginn to run SLOW - System clock is not RTC = REAL TIME CLOCK which is independant of this changes..

But this can be taken back to normal just with feeding the PLL (Phase Lock Loop) of the Clock generator with the actual speeds it is looking for like 24 Mhz for the floppy and 14.31818 (Reference clock ) for the system clock..

ON a X86 MOBO then someone can change (using DMI and also Bios Modifications Programs )the whole thing to DYNAMIC CLOCK - needs a little knowledge of Assembly etc..Anyway it's interesting stuff to do and exactly this way I overclocked a 200 MHZ Pentium Pro Cache 512 to a mere 400+ MHz ..and It doens't CRASH even under heavy loads and by 24*7 times run... I already once posted the link I hope you don't mind if I post it again...

Overclock

This just to prove that this really can be done..

hope this gives you the answer you were looking for..

[DrZaius]

Wow Thank's for the link and info Hpro, I'll have to take some time to look over it. The more I know the better, though.

[Toaster]

In essence, that is correct.
Most CPUs start out as RISC and then evolve to CISC.
RISC- Reduced Intruction Set Computing
CISC- Complex Instruction Set Computing

All Intel based CPU`s for the home user are CISC. This includes the lowly 8088 to the newfangled P-4.
The big differences in RISC are what HPRO suggested and something he didn`t, the ability of the CPU to complete MULTIPLE TASKS in one clock cycle or complete 1 task in fewer cycles.
In the MIPS R4400 S/C CPU for example (Used in SGI systems from the Indy to the Indy2 including servers and the like), the CPU can work 3 computations in a clock cycle or complete any given instruction (1) in 1/3 of a clock cycle.
So lets assume a 300mhz RISC CPU. In this CPU, it can execute an instruction in 1/3 of a CPU clock cycle or 1 insruction in 100mhz of CPU time.
In the R5000 S/C CPU, this rises to 5 instructions per cycle.
In the R10000 S/C, this rises again to a maximum of 8 instructions per cycle.

Theoreticly, here is how RISC and CISC compare.
Lets assume a 100mhz CPU that is not "superscalar" meaning it can only execute 1 task per CPU cycly.
Lets assume the RISC CPU IS superscalar (5 instructions per CPU cycle).
Lets assume that both CPUs run at 200mhz.
In theory, the RISC based CPU should do 5 times the work as the CISC CPU meaning the CISC CPU would have to run at 1ghz to carry the same work load as the RISC CPU.
In actual use, including CPU overhead and the like, the CPU is well over twice as efficient as the CISC unit.
In SGI eguipment, again the R10000 CPU, the base CPU clocks at 175mhz.
However, it outruns the 250mhz R4400 CPU by almost 2:1.

In overclocking, the SGI and SUN systems have no "CPU jumpers" but rather the CPU frequency is selected onboard the CPU via "oscillator crystals".
In my case, I replaced the crystals with faster units.
The R5000 CPU is a "3X" CPU tjhat multiplies the crystal frequency by a factor of 3 to derive the final CPU "clock" or frequency.
Throw onto this the O/S itself and its overhead. Almost all RISC based systems are "unix" or unix like O/Ss that are far more efficient then those from Micky$oft. Copuple this with all that HPRO suggests and you start to see the whole picture. I have overclocked almost anything computer related. The SUN and SGI stuff just makes it simple and clean as well as fast.

BTW:
There are "soft windows"'' software that allow CISC compatability but at a somewhat high cost of performance.


(anywhoo, who could resist the SGI start-up "diddy"!)

[DrZaius]

Great summary, thanks for the info Toaster! I just have a few questions...

Can you have dual SMP RISC processors?
Why don't they replace x86 processors?

And, what operating system (specifically) are you using to run these processors and what programs can you use to take advantage of these multi-calculations?

Thanks.

[Hpro]

Hi,
To answer your question - I saw some small business sever having 4 Sparc's connected to them - Free air out of the case - build onto a Add on card - and heavy 12 Inch fans blasting at it to keep them cool..but so beautifull to look at this machines... (this was some 4 years ago Win98 had just debuted)

to the other question it's because RISC (most of them) are 64 bit processors and so the whole Windows OS line including Win2k XP just all of them would have to be re written since its' quite difficult to run 32 Bit applications on a 64 bit processor - there must be some compatiblity code used otherwise the programs will not even start - but there is now to come from Intel the PIII - 800 and 900 Mhz Itanium (RISC ?) 64bit Processor (link below)
Intel Itanium
This may gives you a Idea what's all about..

[Floppyman]

This all sounds quite intriging to me, how much would you have to shell out to get a hold of a used sun or sgi system? Thousands? Or how about building one, if it's even possible?

EDIT: K, I found a ton on ebay, what would be a good beginner system to look after? Plus does anyone know of a site where I could learn more about solaris, the operating system SUN uses? Thanks.

[Floppyman]

Also,

Can you use regular cdrom and floppy drives in these, or do they have to be special ones that are only used by SUN systems? Thanks again.

[Toaster]

Hi folks,
The SGI and sun systems are SCSI based and use standard SCSI peripherals.
There are exceptions however.
The extreme high end SGI 320 visual workstation uses IDE devices and SGI has moved to other units.
All MIPS CPU based systems "have" SMP capabilities.
All SUN SS/10/20 can handle 4 CPUs directly.
In SGI, one has to get into the O2 and Origin systems for SMP systems.
Virtually all RISC based systems use Unix or a variant of Unix but many have "soft windows" capabilities via software.
In the systems i`m dealing with (SGI Indy and Indigo2) and SUN (ss10/20) are fairly low priced. One system, an SGI Indigo2 system sports a MIPS R10k CPU and "maximpact" graphics and was bought for 500.00.
On Ebay, the SGI Indy with 8 or 16 bit graphics are cheap at being about the 200.00 mark complete with a full install of IRIX6.x (SGI unix) but no media.
On the sun side, there is systems from 100.00 to 400.00+ depending on configs.
Remember that SGI graphics are world renowned and after 5 years can still stomp the fastest graphics that the Intel platform has to offer.


BTW: The MIPS 10K CPU is now buzzing along at 250mhz up from 195 and still room to grow. The Indy with a R4400/2mb SC is whipping along at 250mhz up from 150mhz and still seems anxious to please. More as it comes in.

[Toaster]

A little addendum here:
Solaris for both the Intel and Sparc is cheap.
I recently bought Solaris8 (3 months old) for 60.00 complete 12 disc set which includes many many apps and other goodies.
I also hear that Solaris 8 for Intel is free for the download or from suns web page for 70 bucks shipped to your door.
Irix is another matter. Irix is SGI specific and will not run on any other brands of equipment and there are varying distros for differing types of systems including a "all systems" distrobution that covers ALL SGI equipment.