Does 800Mhz Pentium 4 run hotter then 533Mhz Pentium 4?!!

[Dance123]

Does an 800Mhz Pentium 4 run hotter then a 533Mhz Pentium 4 of the same clockspeed?! Is there much difference in temperature (C°) between those 2 models?

Or is it it the use of dual-channel DDR400 that makes them run hotter?

NOTE: could anyone once and for all clarify if dual-channel DDR400 (let's say 2x 512MB) need additional cooling for the memory or not?!! I would get Infineon or Apacer DDR400 modules. I don't think these have extreme timings or anything and I don't intend to overclock, but still would like to know if these DDR400 modules, especially when installed in pairs need additional cooling?!!

I am asking this question as I have the impression that heatsink/fan manufacturers seem to create more powerfull coolers with perhaps the 800Mhz Pentium 4's with dual-channel DDR400 in mind?

Could anybody please clarify all this? Thanks in advance for all good feedback!!

 

[RaynorWolfcastle]

See for yourself here Intel P4 datasheets
If you look under the thermal specifications you find the following:
2.4A (Vcore: 1.525V, 400 MHz bus, no HT) - 59.8W TDP
2.4B (Vcore: 1.525V, 533 MHz bus, no HT) - 59.8W TDP
2.4C (Vcore: 1.525V, 800 MHz bus, HT-enabled) - 66.2W TDP

Obviously since HT increases the efficiency of the CPU it must be increasing the amount of work done per cycle. Since there are heat losses for all usefull work done there must be heat losses due to the additional work being done every cycle and that is why HT-enabled P4's run hotter than their non-HT brothers (die area is the same but energy output increases).

So a 2.4C will output roughly 10% more heat than a 2.4B assuming HT is enabled for the 2.4C, I'm not sure how that translates temperature-wise though.

Finally, your dual channel DDR400 RAM shouldn't need any additional cooling, assuming you have adequate airflow in your case to begin with.

 

[Dance123]

 

[Corporate Thug]

HT makes it hotter

 

[Dance123]

Hi,

Just wondering, but isn't it so at this moment no program or game makes already use of HT and this is a feature designed for the future, so that it doesn't matter if your CPU supports it or not, or am I wrong about this and will you already see peformance gain with the current generation of apps and games when your CPU has HT?! Any idea how much % performance gain HT gives, and if current games/apps make already use of this feature?!

PS: is HT something that is always on when your CPU supports it or is this something that switched on/off? I wouldn't know why you would set it to off, but just wondering if you couldn't disactivate it by accident without knowing if it is on or off?

Could anybody please clarify this?! Thanks in advance!!

 

[yhelothar]

You can turn HT on or off. HT does not need support, it basically gives your CPU more execution units for filling ALU/FPU units, or something along those terms. Most programs will not fill your ALU/FPU, so it will not benefit at all, but instead, it would slow down your processor. Anandtech has an article explaining everything, you might want to read it.

 

[Dance123]

Are you saying that it is sometimes better to have hyper-Threading OFF then ON?! Seems strange as new P4s have HT and I suppose it's on by default, right?! I don't understand it!

Also, do you have a link to the article you were referring to?!

Thanks!!

 

[sman789]

you turn it off/on inthe bios....on by default....the only time you want it off is prolly during benching, but i've never had

HT is fun, having so many programs on then turning on photoshop and having it loadin so quickly

(may be due to ram also tho)

 

[Dance123]

I am really confused now: do current games/apps make use of Pentium 4's Hyper-Threading technology or not?!!

And why can it be a disadvantage to have HT on (isn't it supposed to be on all the time?!) and how can this slow down your processor?!!!

Could anybody please clarify all this as it is all very confusing to me!! Thanks!!

 

[mechBgon]

Ok, here goes:

• Sometimes HT increases performance
• Sometimes it decreases performance
• Sometimes it's a wash
• It's Windows (WinXP, to be specific) that uses HT. Not the applications themselves.
• If you have two ongoing CPU-intensive applications running at the same time, WindowsXP can use HT to make them run smoother than they would with HT turned off (usually)
• With HT enabled, the combined workload of the two applications may be accomplished more efficiently even if neither one runs as fast as it would by itself

 

[Dance123]

And when does HT decrease performance?!!..

I thought HT sometimes helped and sometimes did nothing, but never thought that it would decrease performance! That's what I still don't understand!..

 

[wicktron]

Because of having a virtual secondary CPU, there is a slight overhead.

 

[Dance123]

Sorry for the newbie question, but could you please explain what "overhead" is?

 

[yhelothar]

as i said.. go read anandtech's article... it explains why it decreases performance