small Pentium 4 buying guide

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jojo4u
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small Pentium 4 buying guide

Post by jojo4u » Fri Apr 01, 2005 5:38 pm

small Pentium 4 buying guide

I think everybody now knows about the Prescott. Intel developed the first multi-functional CPU. It cannot only do all the work in you PC, you can also use it for much more: http://home.arcor.de/jojo4u/silentstuff ... escott.swf.

So the Prescott is hot. But you want to buy it nevertheless. Maybe because you thrust Intel more or you need the extra power in multimedia applications.

So let's list, what Prescotts are available for the designated future socket 775:

Code: Select all

type    Ghz     Cache   TDP     C1E     EIST    NX      64bit
520     2.8     1024    84                              
530     3.0     1024    84                              
540     3.2     1024    84                              
550     3.4     1024    115                             
560     3.6     1024    115                             

520J    2.8     1024    84      x               x
530J    3.0     1024    84      x               x
540J    3.2     1024    84      x               x
550J    3.4     1024    84      x               x
560J    3.6     1024    115     x               x
570J    3.8     1024    115     x               x

630     3.0     2048    84      x       x       x       x
640     3.2     2048    84      x       x       x       x
650     3.4     2048    84      x       x       x       x
660     3.6     2048    115     x       x       x       x

TDP - Thermal Design Point

The TDP is Intels guideline for the sizing of the cooling solution, it does not represent the maximum power reachable:
Chris Hare wrote: The Estimated Max Power Dissipation numbers are based on the fact that Intel estimates the power dissipation for various software applications and sets the Thermal Design Point as the upper limit for how far these applications might push the Pentium 4. Intel states: "Processor power dissipation simulations indicate a maximum application power in the range of 75% of the maximum power for a given frequency." So the Est Max Power Diss was calculated by dividing the TDP by 75%.
http://users.erols.com/chare/elec.htm#intel


Nevertheless you want obviously a TDP of 84W since the higher clocked cores are needing more power.

C1E - Enhanced Halt State

This means that your CPU clocks itself down to 2.8Ghz and lowers the voltage from 1.4V to 1.2V automatically when there's nothing to do. You need BIOS support for this and Windows XP SP2.

So what are the advantages? Have a look at the following picture:
http://www.hardwareluxx.de/jens/Benchma ... =51&cid=80
On top you can see the new Extreme Edition 3.75Ghz which has no C1E enabled. Following are the 560-540 types without C1E as well. Then you can see the C1E-enabled 570J with around 27W less AC power of the whole system.

EIST - Enhanced Intel SpeedStep

This is a bit like Cool'n'Quiet but not as powerful. It works together with C1E, so there is no change in idle power usage.
But when the CPU is between idle and full power, there are now intermediate frequency/voltage steps from 2.8Ghz upward existing.

What does it bring? Please have a look at the last picture:
http://www.computerbase.de/artikel/hard ... gsaufnahme
The first set is idle - EIST has no advantage
The second set is HD WMV playback - EIST cuts the power by over 20W AC
The third set ist burning the CPU - EIST has no advantage.

Unfortunately, EIST doesn't seem to switch to highest power whenever it could be:
1. tomshardware.com reports that encoding a MP3 with lame needs 10% more time with EIST enabled (but leaves them uncommented ;)
2. hardtecs4u.de reports that compressing with WinAce needs 5% more time and games loose around 1 frames/sec
3. computerbase.de reports that during rendering the CPU sometimes refused to clock up

In this light, EIST seems to be a bit too much biased towards power-saving. I will add new reports about that.

Conclusion

From a low-power standpoint it is best to buy a 520J-550J or a 630-650 model. EIST is a little bit difficult to judge nowadays, but giving the problems with the benchmarks, I would disable it until it becomes fixed.

ilh
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Post by ilh » Fri Apr 01, 2005 7:09 pm

Question for you: what is a 3.2GHz P4, 1MB L2, and 64-bit extensions? Our Dell Precision 370s at the office have this processor, and yet your table does not list this configuration.

SpHeRe31459
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Post by SpHeRe31459 » Fri Apr 01, 2005 7:55 pm

You have a Precision workstation, so it is almost guaranteed that you have a Xeon and not a P4. The features you mention fit the basic Nocona core Xeon, which had the 64-bit support some months beofore Intel brought it to the desktop (P4). Link. Unless Dell has some secret batches of P4s that even Intel doesn't list. Perhaps they are the normal P4 640 series chip with defective cache so they disable 1/2 of it and sell it off cheap to OEMs.

ilh
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Joined: Sat Jan 08, 2005 3:31 pm
Location: Acton, MA, USA -- Folding for SPCR

Post by ilh » Fri Apr 01, 2005 8:15 pm

That does look about right. I find it interesting that Dell calls this "Pentium 4 Processor 3.20GHz, Intel EM64T, 1MB/800" and not Xeon. You would think they would want to use "Xeon" for marketing reasons.

Any chance Dell has been quietly selling 541s early? We got these last fall.

Mats
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Location: Sweden

Post by Mats » Sun Apr 03, 2005 5:38 pm

ilh wrote:Any chance Dell has been quietly selling 541s early? We got these last fall.
The best way to find out is to use the Intel Processor Identification Utility.

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