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Thermo probe

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f155mph

Member
Joined
Feb 21, 2001
I got a new p4 1.6a I want to put a probe on it. But how and where can you mount to probe to? What do you guys use to make it stay?

Thanks
 

Diggrr

Underwater Senior Member
Joined
Nov 29, 2001
As long as the probe tip is slim enough to not interfere with the hsf's seating on the core, you can put a dab of thermal goo on the tip, and butt it right up against the edge of the core. Use a bit of silicone to hold it in place using tape until it's cured. The silicone can go on the brown substrate.
It's also easy to peal off incase of RMA or upgrades later.

Have fun!
 

Hoot

Inactive Moderator
Joined
Feb 13, 2001
Location
Twin Cities
I believe the P4 has an internal thermal diode that will give you an excellent core temperture reading. Some motherboards support reading it and some don't. For those that don't and which have a SMBus header on them, you can get a module which allows you to read it. Consult your motherboard manual. You may already be able to read it and just don't know it.

Hoot
 
OP
f155mph

f155mph

Member
Joined
Feb 21, 2001
Hoot,

I know the P4 got the internal probe but my mobo get crazy readings from it. One minute it's at 25c the next is at 70c. It constantly jumps all over the place. Right nowI got some double sided tape that I am using that came from the ram sink. But I dont thing it will hold in the long run.

So silicon and goop eh. Where can you get the goop? Radio Shack? I really don't feel like mail order cause it such a small order.

Thanks ALL
 

Hoot

Inactive Moderator
Joined
Feb 13, 2001
Location
Twin Cities
The thermal diode inside the P4 and Athlon XPs responds to load changes and their ensuing core temperature changes almost instantaneously. It is not unusual to see the temperature jump all over the place, but not from 25-70C, unless you're using a ramsink for a heatsink. With an average HSF, 25-40C would be normal. You can sit and watch the temperature readout while running prime95 and it dances all over the place.

Hoot
 
OP
f155mph

f155mph

Member
Joined
Feb 21, 2001
Hoot,

Wow that really sucks. So how would I know what temp the cpu is really at? I am using a maze2 block, two 12x5x2 rad, inline pump, and four 120mm fans. I taped the probe to the side of the cpu and my temp is at 36c, ambient is like 80F, and h2o is at 27c the cpu is a [email protected] at 1.5v.

Oh yeah how do you manage to keep your temp so low with your rig? I know you are only using one 6x6x2 rad and two 120mms. Thanks for all the help HOOT.
 

Hoot

Inactive Moderator
Joined
Feb 13, 2001
Location
Twin Cities
I use the highest temperature I can catch. Prime95 does not exert a constant load on the CPU. The load varies depending upon whether the program happens to be running the calculation, saving results to disk, reading from the disk, etc. I figure the highest temperature is probably close to running the CPU at its true wattage rating for a given speed and core voltage. Now if you want to see real maximum wattage yield, you run the BurnCPU utility appropriate for your CPU. BurnK7 typically runs my CPU cores a full 4-5C hotter than the highest temperature I see with Prime95 Torture with the priority set to 10.
Unlike Prime95, when using Burnk7, the temperature does not dance around.

If you watch my signature throughout the year, you will see those core temperatures vary somewhat. It all depends upon what season we're in. Right now, winter is still reining up here in Minnesota. My PC room is in the basement and the concrete floor is typically 15C, even though the temp up at chest height is 20C. My tower sits on the floor (where they belong) and sucks that cool 15C air right into my radiator. Later this year, in the peak of the summer, the floor will be more like 20C when the room is 25C at chest height and my temps will be higher.

Hoot
 

Koooler King

Member
Joined
Nov 21, 2001
Location
North America
As per previous replies, the internal diode is the most simple way to go. If you really want to get serious about temp monitoring, then the next alternative is to sink a thermocouple into the heat sink base and go from there. I know a few people who have done that, so here goes if you so desire ...

If you have a typical heat sink with a 0.25" (6mm) thick base, using a machine shop quality drill press, slowly and carefully drill a hole through the side of the base into the middle. A 0.032" (.75mm) drill bit is ideal. It takes a great deal of patience and experience to do this. If successfull, you can then insert a standard wire thermocouple of that size half way into the heat sink base.

Do realize there is a lag in time response from the cpu to the heat sink (and through the grease) if you are trying to control temps that way. Not for the faint of heart!

Good luck!

Koooler King
 

rossd

Registered
Joined
Nov 16, 2001
Location
Silicon Valley California
Making a thermal diode reader is fairly involved. I spent quite a while tracking down the part (the reader chip). Maxim gives out samples but mine never arrived. I eventually had to pay for them over the web site, and they still took a couple of weeks. Once you have the chip, you'll need to solder onto the leads, which are tiny, without breaking or bridging anything. This is difficult. Hooking it up to your computer is relatively easy.

I wish someone would just produce these so I could buy one. I'd pay $30 for one, and they cost at most $10 in parts.

Regards,
rossd.