View Full Version : GigaDesigns: Big problem of overheating

07-22-2008, 03:19 PM
Hy dudes

I am new here, and i have got a big problem.

I have got a QS GigaDesigns 1.2 Ghz Dual
6800 GT
1 GB of RAM

Now, as some users here also I have got a GigaDesigns Upgrade.

My problem is over a year now the excessive heat.

I tried mostly everything.

Currently I have installed a Everflow Fan with 5100 rpm 41cfm and veeeery loud.

So, my only hope is to reduce the core voltage.

I dont know what my current voltage is, and I havent got the right manual cause I received the wrong with the CPU.

Does anyone of you guys has got the pinout of the corevoltage for my CPU? (Its my only hope :( )

Thank you


07-22-2008, 06:50 PM
I don't think reducing the Core Voltage will reduce the heat. What will reduce the heat is reducing the clock speed of the CPUs, running them say at 1GHz. At least, that's been my experience.

07-22-2008, 08:16 PM
Just for clarity, are you sure the other fans are working correctly? Good amount of heat coming out of the PSU, etc?

As I recall, the QS cases have a bad habit of recycling hot air......if you want to run the higher clock speed, your only hope may be to modify the case to draw heat out more effectively. Up for it? Check out eric's link in his post at the bottom for the first step. You can do more to get heat out of the case too....but more mods/more work.

If not, downclocking as mentioned is your best bet.

07-23-2008, 12:30 AM
Yes QS/DA have very poor stock airflow. Much can be done by simply changing the direction, and routing. Much easier/more effective than playing with CPU voltages IMHO, but then I'm a hardware-oriented kinda guy.

07-23-2008, 11:08 AM
Hy dudes

Thanx for the replies

Now, i have done pleeeeenty things.

First i modded the case with an air intake at the top...it didnt lowered the temps as expected..

I bought a lot of fans and not all of them worked fine.

I reversed the fan and taped the hole.

I thought Gigadesigns sell the Dual 1.2Ghz Upgrades as Dual 1.2 GHz`?

I know they are overclocked Dual 1Ghz CPU's but they tested it under 1.2Ghz and they garantuee you that it will work, but it doesnt. Thats kinda sad...

And if i clock the CPU to 1Ghz it runs fine with a PAPST fan on it...

Its kinda sad, but i gonna have to clock it down, i did this several times...

Does anyone of you guys have got this CPU Upgrade?

Thanks a lot


07-23-2008, 04:15 PM
I have a dual 1.6 7447A Giga in my DA. It ran fine with the stock fan setup, but the twin 50mm fans were too noisey for me (I do audio work). They are also inefficient since they just churn the air in a circle around the heat sink.

You can see the mods I did to my case in this thread. (http://www.macgurus.com/forums/showthread.php?t=22377)

IMHO trying to stuff cool air in the top of the case is a bad idea since heat tends to rise naturally, and the PSU fan will simply exhaust that air out the back before it has a chance to cool anything else.

07-23-2008, 07:07 PM
I agree with Brane.....heat wanting to Rise and all. But since you did the mod, can you just reverse the fan to make the top an exhaust? The more heat you pull out, the more cool air will get pulled in. Would be best to get the cool air in the bottom with some passive holes, but exhausting may do the trick for overall case coolness.

For the CPUs themselves, building a exhaust duct may be the best option. Suck the heat right off and out, not letting it heat the interior and get recirculated back onto the CPUs. Keep the coolest air possible coming in the case and over the CPUs.

No way to prove if it will work or not unless you try. If it was still a stock case, I'd say go for it. Since you have been modding your case, only you can really say whether or not more cooling could still help.

07-24-2008, 02:40 AM
Agree with unclemac and M.Brane. Since it appears you done a big mod making a hole on the top, maybe you can tweak the stock fan configurations.

Where exactly is the mod "at the top"? On the very top of case?

Just some thoughts:
1. as unclemac and M.Brane suggested, reverse it and make it an exhaust fan.

2. Stock fan mod 120mm mod: with a big exhaust in (1), reverse the 120mm exhaust fan and make it an intake. I don't have a QS (but a DA), and if memory serves the QS had the 120 mm as an exhaust rather than intake. Again, I'm not sure about the QS configuration of the 120 mm fan -- if it's already an intake, leave it as an intake.

I recall this thread (http://www.macgurus.com/forums/showpost.php?p=106272&postcount=12), which makes me think the 120 mm is exhausting rather than intaking cool air.

3. The CPU fan in the plastic shroud. In a QS thats an intake fan. I think you may have already played with this one, but you could tape the hole on top and reverse the fan making it an exhaust fan. In my DA, I used that QS rubber housing and used it as an exhaust with a Giga Dual, see my signature for a link to that report. In my DA I did see some temperture drops in that configuration.

I guess in the end, part of what I'm suggesting -- if I understand your hole-on-top mod -- is configuring the stock fans as a DA rather than a QS.

07-24-2008, 06:18 AM
Thak you a lot dudes

I really did mostly everything, i throwed my old modded case away and i have got now a stock case.

So, i decided to clock them down to 1Ghz and now they run very confortable.

My 120mm is an intake fan and i also reversed the CPU fan.

Thank you guys, my problem is solved :D

A link to a very good temperature control for noisy fans:


I built it too, and it runs since yesterday in my QS, its very cool this control...and easy to build


07-24-2008, 12:40 PM
First i modded the case with an air intake at the top...it didnt lowered the temps as expected..I would think anything at top you would want to exhaust out since hot air rises. Bring cool air from below and across components to cool.

07-24-2008, 01:39 PM

Thank you a lot guys

I solved my problem since yesterday :D

My tempcontrol works really sweeeet...


07-26-2008, 03:50 PM
Partially i solved it :(

It drives me really biiig nuts.

I want to play X-Plane.

First time it works good.
Second startup a partial black screen with white letters. Debugger info and so on.
3. startup it hangs up itself.

May it crashes because its a Betaversion, i stressed the G4 with rendering in Maya for a half hour, it works fine.

Now i have got a question i replaced my old thermalpaste which was kinda bad with industrial paste :Amasan T12, it does its job fine i wann say.

My question is. There are two black big electrical parts on the CPU Board which are in the front, the heatsink also cover them and in the heatsink theres a part which is cutted out, here is the place were those two parts are.

They become very very hot, i cant even touch them, i think easily over 100 Celsius.

Should i try to put some paste on them? (It hasnt had any on it, originally)
A part which is also getting pretty hot, are those two copper flat things, on one
is GigaDesigns engraved.)

News: During editing an image in Photoshop it freezed completely...

Do they become also so hot on your CPU's?

Could there be a defect on the CPU Board itself?

My beginning problem was: I used the CPU on the first day for good 8 hours within Maya (rendering and so on) then i opened the case and touched the heatsink, it was so dammmn hot. after that upgrade i had sooo much KernelPanics easily over 50 over a half year, then i tried mostly everything, and today I clocked it down, but it still has got some problems.

Unfortunately i havent got any warranty, because i use another fan, I putted some other paste on it, and my heatsink looks kinda bad, cause with my new fan on it, i had to screw it between the fins)

Thank you a lot


07-26-2008, 05:11 PM
If you look at the bracket I made for my CPU fan it covers the entire heat sink. This forces the air to flow over/through the entire thing, and none of it gets recirculated since the fan exhausts out the back. The bracket itself also adds to the heat sink surface area.

Thermal paste itself cannot provide cooling. It's purpose is to simply fill in any tiny gaps in the contact area between the chips, and the sink. A common problem with it is putting too much on. Just a tiny bit is needed.

I've never had the sink off my Giga, but I've done quite a few G3s. I polish the bottom of the sinks to a nice mirror finish, and clean with denatured alcohol. I've never had a problem with cooling on any of 'em with just a very thin coating of paste. Sometimes I don't even install fresh paste if the existing is still in good shape i.e. can be smeared with my finger tip. When I do install fresh paste I make sure to remove all the old stuff with denatured alcohol.

All that said my Giga never gets hot only moderately warm. Definitely touchable. It is a 7447A though which are lower voltage/cooler running chips than the 7455s.

08-06-2008, 11:09 AM
Hmm..My fan also covers this black thing, as said its not the original fan its a 70mm fan on it.

But i really dont know why those two flat parts are getting so hot. This two things i think cool the two voltage regulators...

I dont know what i can do anymore.
I gonna run Maya and render an image for 1 hour, if it then runs stable, then its def. X-Plane if not, then its also something with the heat...

Thank you a lot guys


08-09-2008, 04:01 PM
I don't think reducing the Core Voltage will reduce the heat. What will reduce the heat is reducing the clock speed of the CPUs, running them say at 1GHz. At least, that's been my experience.

Reducing the corevoltage does reduce the heat ;)

The less the power the less the amount of heat.

On Intel CPUs this can be more than 20 celsius undervolting them ;)



08-10-2008, 04:54 AM
Sounds pretty sweet..

In some way, i knew it was something with the corevoltage.

Is there anyone from GigaDesigns or has got this CPU and can the tell me the jumper settings? (Its my last option...)

My CPU came with a wrong instruction sheet...

Thank you guys

Does lowering corevoltage also lowers the clockspeed?


08-10-2008, 09:46 AM
Sorry, I only have a single '47 1.6, so I expect the jumpers are different. Somebody here must some info for the duals.

08-10-2008, 10:53 AM

I hope anybody has got some infos on it...its my LAST option...

Thank you


08-10-2008, 11:06 AM
Is this (http://www.xlr8yourmac.com/G4CARDS/giga_designs_125Ghz/index6.html) the one?

08-10-2008, 12:26 PM

Thank you

Unfortunately it is not this CPU.

Its called G-Celerators M-Series

It has a copper heatsink and Dual CPU.


08-10-2008, 04:38 PM
Which CPUs on the Duals? Mine was the 7455s, I may have the pdf version somewhere for that one. But I can tell you straight away that the manual only included clock-speed jumper settings. It did/does not have any information on Core Voltage settings. Giga Designs never seemed to release those setting publically for the 7455 M-series upgrade.

08-14-2008, 04:56 AM

Thank you for your fast reply.

Ahmm..i gonna have a look at it.

But what I really dont understand is, why the CPU can work flawlessly and then sometimes total horrible.

And i also cant understand why i have received a wrong manual and a CPU which isnt the same as shown on the box.

And has Gigadesigns ever sold a CPU with a Dual 1.2 Ghz CPU 2 MB L3 Cache? (Or have i got kinda a miss?)

Thank you