P4a or P4b

[5614]

I'd always read/thought that there were 2 versions of the Pentium 4 processor.

 

The first one:

No hyperthreading

No overheat auto-shutdown protection

 

Whereas the second edition had both of these. Due to the age of my computer (relative to when the P4 processor was brought out) and the fact that I do not have the hyperthreading option in my BIOS I believed that I had the first edition.

 

However just now I turned my computer on without the heatsink in (deliberately) and (the processor started at room temp) by the time it had booted just windows, hadn't even loaded my username the computer shut down, I felt the processor and burnt myself.

 

1) That took like 20 secs (approx) for that processor to overheat, that is seriously quick (IMO),

 

2) If I have the P4a (or 1st edition) then why did it auto-shutdown, the processor can't have melted because it's working now!

 

So regarding the first/second edition of the P4 processor, does anyone know about them? (because something in my what I thought is obviously wrong!)

[Kedas]

It could also be a setting in your bios to shutdown if temp is higher than what you specified.

[5614]

Would I see this option in the BIOS? Because I don't recall one, though I could me mistaken, is there a posibility that it's hidden from the user?

[Dave]

As far as I'm aware, the later version of the P4 doesn't automatically shut the computer down, but downclock itself to a very slow speed to avoid burning the processor out. There's a cool video on Tom's Hardware somewhere about that.

[5614]

That does ring a bell (slow clock speeds), my processor certainly shut down entirely though, interesting, I'll try doing some searches tomorrow.

[Dave]

It's not a huge leap of logic to assume that the earlier P4 switches itself off, and they improved upon this in the second version. I have to say that I don't know for sure though, and I'm too lazy to be searching atm

[5614]

All sites I can find on the matter talk about a Thermal Control Unit which reduces clock speeds when overheating occurs. Interesting.

[insane_alien]

my P4 clocks down. NEVER run xp at 100Mhz

[H2SO4]

You Can Barely Run Win95 At 266mhz

[insane_alien]

i know but thats what my processor clocked down to when my heatsink was loose.

[Dave]

I'd rather find out that way than through an older AthlonXP blowing up in my face

[MattC]

I could be mistaken but I believe that even P3's have some measure of protection against overheating ... I believe I read that on Tom's Hardware, when they tested a whole bunch of CPU's to see which ones they could burn out.

[Dave]

Yeah, most do and have done for the past 5 years or so. It's just the older Athlon XP's that tend to ignite these days - the later ones have overheating protection.