At what temp does the P4 clock throttle kick in?

[John]

65C?

 

[Antoneo]

I thought it depended on the throttling temperature you set in the bios? I think I saw that in my EPoX 4g4a...

 

[mechBgon]

I thought it was 78C. It doesn't answer that particular question, but you may still find this article interesting too.

 

[John]

I should have mentioned I am using the Epox 4BDA2+

I see a dram read thermal mgmt & delay prior to thermal setting in the advanced chipset features. It looks like 70C is the temp setting to clock throttling.

 

[THUGSROOK]

67*C

 

[John]

Originally posted by: THUGSROOK
67*C

Actually I am not sure that is an accurate number.

http://subscriber.anandtech.com/arcmessageview.cfm?catid=28&threadid=775629&highlight_key=y

There is some good info in the URL above, and in fact it was your thread.

 

[THUGSROOK]

i'll stick by my 67*C answer

 

[John]

I am at 68C right now running Prime95 and I see no evidence of clock throttling. Could you please show me something to back your claim up?

 

[DizzyNT]

i doubt anyones actual cpu temp is accurate or what they intended to be "clock throttle" accurate

 

[BEIF]

THUGSROOK is right - for a 1.6A, throttling starts at 67C - the CPU itself will keep working all the way up to 134C [albeit ultra-throttled-back] and ultimately " go critical and shutdown" at 135C - check the Intel spec sheets if you dont believe.

Two golden rules to stick by - keep your voltage at 1.70v or less and keep your load temp as far below 67C as you can.


Benny [BEIF] Ifin

 

[John]

Originally posted by: BEIF
THUGSROOK is right - for a 1.6A, throttling starts at 67C - the CPU itself will keep working all the way up to 134C [albeit ultra-throttled-back] and ultimately " go critical and shutdown" at 135C - check the Intel spec sheets if you dont believe.

Two golden rules to stick by - keep your voltage at 1.70v or less and keep your load temp as far below 67C as you can.


Benny [BEIF] Ifin

From the URL I linked to, 68~71C seems to be the start of the throttling.

 

[THUGSROOK]

the clock throttle is a temp switch, not a temp "sensor".
it engages (throttles) at 67*C.
your moboard may or may not show that same temp.

my max temp is only 44*C during prime95 so i personally have nothing to worry about.

68*C? :Q

 

[DivideBYZero]

Originally posted by: John
I am at 68C right now running Prime95 and I see no evidence of clock throttling. Could you please show me something to back your claim up?

And People shout down AMD for running hot!! My 50% OC'd T'Bird never goes over 48*C load, but then it does have two 50CFM case fans that risk pushing the box clean across the room if I take the locks off the wheels.....

 

[async]

From the P4 data sheet

"Thermal Monitor uses two modes to activate the TCC: Automatic mode and On-Demand mode. Automatic mode is required for the processor to operate within specifications and must first be enabled via BIOS. Once automatic mode is enabled, the TCC will activate only when the internal die temperature is at very near the temperature limits of the processor."

I disabled mine in the BIOS (without knowing what the option was for) and lo and behold, my P4 runs at 76C. Ouch
I assume the TCC uses the value from the thermal monitor (which will be the same temperature that your BIOS will show).

So, the P4 will throttle back, the data sheet doesn't give an exact temperature at which this will occur (or I missed it), but only if the feature is enabled in BIOS.

 

[BuddyAtBzboyz]

Originally posted by: DivideBYZero

Originally posted by: John
I am at 68C right now running Prime95 and I see no evidence of clock throttling. Could you please show me something to back your claim up?

And People shout down AMD for running hot!! My 50% OC'd T'Bird never goes over 48*C load, but then it does have two 50CFM case fans that risk pushing the box clean across the room if I take the locks off the wheels.....

Yeah I don't expect a p4 to ever hit 67C unless the hsf falls off.

 

[John]

I unplugged the fan for a minute and the temp climbed to 80C, but I never saw the system stuttering, or the real time clock on WCPUID change from 2.82GHz.

 

[THUGSROOK]

WCPUid doesnt work on clock throttling

run a benchmark next time - its throttling

 

[WarCon]

Isn't there two thermal diodes on a P4? One is for the throttle and shut down and one is for the bios monitoring. They are located in different sections of the core, so I would assume its possible that the measured throttle temperatures may vary (probably not by much though).

I also wonder why can't mobo manufacturers just display the data from the diode without tampering with it. Shouldn't all mobo's measure the same chip at the same speed with the same voltage and the same heatsink to be nearly the same?

 

[MrThompson]

Read through what Intel has to say about it. Note the diode that controls the clock throttling is in the hottest part of the chip. The diode your motherboard reads (if it can) is in the cooler cache. The only way to tell if a hot running overclocked CPU is throttling, is to benchmark it with Prime, Seti, etc.

A side note, clock throttling has some interesting implications if an overclocked P4 is used or HS or thermal grease testing. It's possible the low end products may test better due to throttling.