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Confusing P4 550 with E0 PRB=1 etc etc.

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Anonymous
December 10, 2004 12:27:50 AM

I've been reading this article:

<A HREF="http://www6.tomshardware.com/cpu/20041115/index.html" target="_new">3.8 GHz P4-570 and E0 Stepping To End Intel's Performance Crisis</A>

and although it's a good article, i find myself (for the first time) slightly confused by the options and different P4's available.

I'm going to build a new P4 system in January, and just for the sake of clarity i'll give you the most important specs as they are set right now.

-------------
P4 550 3.4GHz, Asus P5AD2-E Premium,
2*512Mb Corsair TwinX Matched Pair 675MHz PC5400 DDR2
ATI X700 or X800 (PCIe) Vid. Card. (depends on pricing)
-------------

Question 1:
I'm planning to unlock the multiplier, set it to 14x and overclock the FSB to 1066Mhz. This requires the Performance Requirement Bit to be enabled (PRB=1) doesn't it??

Question 2:
I've been searching on intels site for the P4 550 (PRB=1, E0 stepping and Thermal guideline (=TDP?) 115W), but i can't find it on the Intel site. The article clearly mentions such a P4 550, so this leaves me quite confused.

<A HREF="http://processorfinder.intel.com/scripts/list.asp?ProcF..." target="_new">This is not the correct P4 550</A>

If i'm correct, a processor with all aforementioned gizmo's should also have the following "code": 775_VR_CONFIG_<b>04B</b>, and the P4 550 from the link above have a "04A" spec (= mainstream). The next closest thing with the "04B" spec (= Performance) i can find is a P4 560.

Is the P4 550 ((PRB=1, E0 stepping, Thermal guideline (=TDP?) 115W and 775_VR_CONFIG_<b>04B</b> spec) i want to have available or should i scale it up a notch and got with the P4 560? (it's getting a bit pricy by now :( )

If so, which one is the way to go:

<A HREF="http://processorfinder.intel.com/scripts/details.asp?sS..." target="_new">P4 560</A>

The SL7NZ supports EMT64. Not really nescesary isn't it?? Or could it be usefull in the (near) future when MS releases Longhorn?

I hope it's still clear to you all what i want. Right now, i'm confused........

If somebody could provide me with the correct product code for these suckers, i'd be a happy guy :) , but maybe that's to much to ask

More about : confusing 550 prb etc

December 10, 2004 12:45:49 PM

Have you looked at the "J" models? Like 550J, 560J, etc.
Anonymous
December 10, 2004 10:36:41 PM

Yep, thus far the only P4 550 i could find with E0 stepping has a thermal rating of 84W and it has the 775_VR_CONFIG_04A specifications. (S-spec nr: SL7PY)

The J means that the NX bit (non executable bit) has been enabled.

I think i know now what to get and that's the 5xxJ. It has the E0 stepping and should have all the mumbo jumbo (Enhanced halt state, Prb=1 etc) attached to it.

Although i'm quite sure about the J, the thermal design limit and the 04A spec still confuse me. If it's an E0 stepping, it should be a 115W 04B spec shouldn't it??
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December 11, 2004 3:36:03 AM

You'd think so, but they could have changed all that with the new stepping of course. Did Intel pull another sneaky? By the way did you notice the SL7PZ footnote that says it has EMT64?
December 11, 2004 6:34:46 AM

FYI 04b is the bios recognition code. That is, the bios update, so that the newer speed can be recognized.
December 11, 2004 2:30:55 PM

MartinS

Like you I am also building a new PC of virtually identical spec in January, although probably without as much overclocking. I also find the Intel specs very confusing, and in some places contradictory.

I am not sure whether the Performance Requirement Bit needs to be enabled for overclocking. I think it means it just includes the technology for better control of the temperature. If it does require PRB=1 then none of the 550J suffix processors have this, only the non "J". Look at SL7J8 and SL7KM which are non-J and 04B.

Another complication is that not all of them are available as boxed items, the only 550J available in a box is the EMT64.

It would be simpler to go for a 560J, as (at least in the UK) this appears to be the only J suffix processors currently available.
Anonymous
December 12, 2004 12:40:26 AM

First let me apoligize for the somewhat long (or maybe complicated posts) and begin by telling you about some of the other things i found.

The 04A means that the processor is meant for mainstream use. The 04B means the processor is meant for high mainstream and performance systems. As you will see later on, some of the 04B processors are also compatible with the new BTX form factor. Why only some of them are compatible is a mystery to me.

Motherboards that support "04B processors" are backwards compatible with "04A processors". 04B processors CAN NOT be used on a mobo that only supports 04A proc's.

(source: <A HREF="http://www.intel.com/cd/channel/reseller/asmo-na/eng/pr..." target="_new">Intel P4 775 integration overview</A>)

Now, about the 550 mistery...look what i found:

Pro.Nr. Freq - PCR - PRB --- Stepp. - TDP(W) - Boxed Processor
570J -- 3.80 - 04B - PRB=1 - E0 ----- 115 ---- xxPG3800EJ*
560J -- 3.60 - 04B - PRB=1 - E0 ----- 115 ---- xxPG3600ET**
560J -- 3.60 - 04B - PRB=1 - E0 ----- 115 ---- xxPG3600EJ*
560 --- 3.60 - 04B - PRB=1 - <b>D0?</b> ---- 115 ---- xxPG3600E
550J -- 3.40 - 04A - PRB=0? - E0 ---- 84 ---- xxPG3400ET**
550 --- 3.40 - 04B - PRB=1 - <b>D0?</b> ---- 115 ---- xxPG3400E
<i>* These processors are E0 step processors and include support for Execute Disable Bit, Thermal Monitor 2, and Enhanced Halt State.
** These processors are E0 step processors and include support for Execute Disable Bit, Thermal Monitor 2, and Enhanced Halt State. These processors are compatible with the Balanced Technology Extended (BTX) form factor.
(source: <A HREF="http://www.intel.com/support/processors/pentium4/sb/cs-..." target="_new">Intel P4 Product order codes</A>)
</i>

When you take a closer look at the 550 series, something strange is going on:

The 550J (which in theory is “more advanced”) has a 04A platfrom compatibility rating (let's call it PCR. it's a lot shorter :wink: ) and therefore a lower TDP.

The “normal” 550 on the other hand has a 04B PCR and a TDP of 115 Watts.

I haven’t found info about the 550J PRB that gives me 99% certainty about it’s state. Everything points towards PRB=1, but the PCR 04A contradicts that.

The 560 is almost as weird. It comes in no less than 3 flavours.
They all have PCR-04B and PRB=1, and therefore a TDP of 115W.

There is a 560 without Execute disable bit. A 560J with Executable Bit and last but not least:
a 560J with Executable Bit <b>AND support for the upcoming BTX form factor</b>. The only difference I could find between the latter 2 are the differences in Product Order Codes.
(blabla PG3600ET and blabla PG3600EJ)

It looks like the 560J with the BX80547PG3600ET** ordercode is the one to get, as i'm still not sure what to think of the 550.

On one hand I’m finding answers to my questions, and on the other hand I’m raising new. *sigh*


[edit]
I was looking at my post, and it suddenly came to me that P4 550 and 560 without asterixes behind theorder code do NOT have the preferred E0 stepping. However, i'm not entirely sure what the consequences are....
[/edit]
<P ID="edit"><FONT SIZE=-1><EM>Edited by MartinS on 12/11/04 10:10 PM.</EM></FONT></P>
December 12, 2004 7:37:07 AM

MatinS

Thanks for that, a good very good analysis, clearly presented, and it has helped me to clarify my thoughts.

My findings are generally the same as yours.

All current P4 processor specs can be found here: <A HREF="http://www.intel.com/design/pentium4/specupdt/30235210...." target="_new"> Spec </A>

The PCR refers to the motherboard voltage regulator specification (see: <A HREF="http://www.intel.com/design/pentium4/guides/30235603.pd..." target="_new"> Voltage Regulator Down (VRD) 10.1 Design Guide For Desktop LGA775 Socket</A>). From reading various non-Intel sources I think that when the 550J was introduced its new core had lower power requirements than the 550, presumably also helped by the use of Thermal Monitor 2, and Enhanced Halt State. Therefore, the 550J can now specify the 04A PCR for motherboards, rather than 04B for the 550.

From reading <A HREF="http://www.intel.com/design/pentium4/datashts/30056102...." target="_new"> Intel® Pentium® 4 Processor on 90 nm Process Datasheet </A> I think the PRB is simply a flag to the motherboard to define how the voltage regulator is to be set up, I don't think it changes anything in the processor itself. The 04A PCR means a lower power requirement and PCB=0 sets the voltage regulator accordingly.

The question for overclocking is - can the 550J be overclocked in the same way as a 550? Does setting the PRB=0 reduce performance, or does it simply redefine the power draw (and make it 04A compatible)? I <i> assume </i> that the 550 and 550J have the same performance, but when overclocking it <i> may </i> be best to use a 550J in a 04B motherboard and (as usual) pay careful attention to cooling.

On a practical level, is the 550J available in the US? In the UK the 550J is not yet available, but 560J's are. So, if the Execute Disable Bit is required the 560J is the only option, at least at the moment. Unfortunately the 560J will draw more power and run much hotter than the 550J

Does the above discussion agree with your research and views?

This whole subject is very confusing and difficult to understand, and Intel seem to bury information in places where it is difficult to find. Why do they make it so difficult? From reading other non-Intel sources I don't think we are the only ones to be confused, others seem to have only parts of the story.



PS:-

Looking at the <A HREF="http://developer.intel.com/support/processors/pentium4/..." target="_new"> Product Order Codes </A> it shows that a boxed 550J for an ATX board is not available, only for BTX.

It also shows that the all OEM processors for each speed rating are the same, irrespective of whether its a J, BTX, 04A etc! I would assume (although the table does not make it clear) that only the J versions are now being made and supplied to the trade (the BTX difference only applies to boxed versions because only the cooler is different, and an 04A 550J part will work in a 04B motherboard). However, because there are old stocks of the boxed non-J 520/530/540/550 versions still available, the newer parts are not yet offered.


PPS...

BX80547PG3600ET is a boxed processor for an BTX system and the cooler is not compatible with ATX systems. For ATX you need BX80547PG3600EJ
<P ID="edit"><FONT SIZE=-1><EM>Edited by JefUK on 12/12/04 10:55 AM.</EM></FONT></P>
Anonymous
December 13, 2004 3:48:54 PM

Hehe, lol. This shows 2 people can find out more than one. Great job.

Quote:

[...]

From reading Intel® Pentium® 4 Processor on 90 nm Process Datasheet I think the PRB is simply a flag to the motherboard to define how the voltage regulator is to be set up, I don't think it changes anything in the processor itself. The 04A PCR means a lower power requirement and PCB=0 sets the voltage regulator accordingly.

Does the above discussion agree with your research and views?

yes, it does. I found out that the PRB=1 flag has to do with the "Socket Load Line", although i don't really understand yet what that means. Unforutunately, the matter is getting more and more complicated the further you get in to it, but i will continue to read up about it.

Quote:

he question for overclocking is - can the 550J be overclocked in the same way as a 550? Does setting the PRB=0 reduce performance, or does it simply redefine the power draw (and make it 04A compatible)? I assume that the 550 and 550J have the same performance, but when overclocking it may be best to use a 550J in a 04B motherboard and (as usual) pay careful attention to cooling.

Well, i think the difference in theoretical overclockabillity is negligible. However, as the 550 can cope with higher currents it'll be more attractive for people searching for higher overclocks. (Early on in this topic we found out that PRB=1 means TDP=115W)

As i said, i'm getting a P5AD2-E (i925XE) wich supports the CPU lock-free function. I've been reading and searching info on the internet, and i'm now quite sure that PRB=1 is a requirement for lock-free to work (if you have info that contradicts that...??). Earlier on in this topic we found out that PRB=1 means TDP=115W.

Furthermore, i don't think i'll run into much trouble with cooling as i'm getting a watercooled solution, including CPU, chipset, HD and GPU coolers (<A HREF="http://www.koolance.com/shop/product_info.php?cPath=28_..." target="_new">Koolance PC2-901BW</A> which will (hopefully) give me one less thing to worry, and a lot less mony on my bank account. :eek: 
This pc won't be replaced for at least 4-5 years, so it better be something good.

Quote:

On a practical level, is the 550J available in the US? In the UK the 550J is not yet available, but 560J's are. So, if the Execute Disable Bit is required the 560J is the only option, at least at the moment. Unfortunately the 560J will draw more power and run much hotter than the 550J

I don't know if it's available in the US as i live in The Netherlands (i've been posting on rather "un-european" times because i was working the evening/nightshift, and was getting home around 02:00 (GMT+1), and couldn't really get to sleep).

Judging the articles/forums i've been reading, it's quite hard to find a 550, no matter where you are on this blue planet of ours. I understand you (probably) aren't going to overclock your PC as much as i am, so it may be a more sensible thing to stick with the 550J PRB=0, because of the lower power usage.

Quote:

This whole subject is very confusing and difficult to understand, and Intel seem to bury information in places where it is difficult to find. Why do they make it so difficult? From reading other non-Intel sources I don't think we are the only ones to be confused, others seem to have only parts of the story.

Well, this certainly is one thing we agree on :smile:
December 13, 2004 4:13:33 PM

Hi all! New guy to the boards, but i needed some info and this is the place to be i see. Anyways, i too am upgrading this january... seems to be a lot of that going around.

I will be getting an ASUS P5AD2-E Premium Mobo, but my questions deal with memory and cpu. I've read the posts above and am pretty sure i know exactly what to get, but i just want to be sure and confirm.

I want E0 Stepping, Execute Disable Bit, Thermal Monitor 2, and Enhanced Halt State with my new processor, along with prb=1 (i intend to overclock the cpu), so this leads me to getting the Pentium 4 560J (xxPG3600EJ). (BTW i am unfamiliar with BTX, thats why i went with EJ as apposed to ET). Since the P5AD2-E_P supports FSB1066 i want to go ahead and overclock the processor to FSB 1066 and maybe boost the speed up to 3.8GHz or somewhere around there. (i'm gonna take it for granted the stock heatsink and fan aren't gonna cut it for cooling? correct me if i'm wrong please).
SO IS THE PENTIUM 4 560J (XXPG3600EJ) THE RIGHT CHOICE FOR ME?

For memory i plan on getting corsair ddr2-600Mhz as apposed to 533 for the P5AD2-E_P. i should be able to overlock this to ddr2-667 without any troubles yes?

P.S.
Ehhh wrong post, but i'm sure u can help me out anyways... I'm ashamed to admit it's been almost 2 years since i upgraded. Anyways, SATA. Basically the same as IDE as far as setting up physically? New cables and plugs i know. New power interface tho? I'm assuming yes, but can i boot from a SATA drive? (since it's on a RAID controller... UGH i hate RAID, so forgive me if that's an utterly asinine question). I'll be using my old HDD on an IDE channel, shouldn't have any problems recognizing and using both drives right? (i'll have them as seperate drives in windows) And lastly... New DVD-RW, should i get a SATA version or stick to IDE?

Thanx everyone for listening to my rambling, and thanx for your help.

__________________
Logic
Anonymous
December 13, 2004 6:51:42 PM

BTX (Balanced Technology Extended) is the successor to ATX, and provides better cooling/airflow for the various components in your PC case. Since BTX cases are very hard to find and BTX Mobo's (virtually) non-existent until now, that's not something to worry about. Wether the CPU is BTX compatible is also no issue. It's the cooler which has to comply to certain demands.

In my opinion it should not be a problem to overclock the P4 560J. ~3800Mhz@1066 (multiplier 14x) is certainly possible, as long as you provide good cooling.

Something that's important is that you get a GOOD HIGH PERFORMANCE PSU (Power Supply Unit). 9 out of 10 times people that buy a high end pc, are neglecting the PSU. Needless to say that's a bad thing to do as it could destroy the stabillity of the pc, or destroy components of your pc.

don't be ashamed for not upgrading for "only" 2 years. PC's are expensive, and i'm certainly not going to buy a PC on a "regular" basis. The only thing i've been upgrading are my harddrives.

SATA is the successor to IDE. It supports transfer speeds of 150MB/s. Phisycally SATA drives are (almost) identical to IDE. The main differences are a diffenrent data cable (thinner/smaller) and different power cables. Some SATA drives also have a Molex connection. You can just boot from a SATA drive.

About the DVD.....i don't think it will matter very much, as a DVD read at 16x means a transfer of 22MB/s. That's way below the max transfer speed of IDE-100
December 14, 2004 4:02:39 AM

Thanx for your help. I certainly know what u mean about a PSU. I planned on getting an Antec 2fan 450watt PSU (http://www.newegg.com/app/viewProductDesc.asp?descripti...), i was thinking 450 would be fine, but should it be higher?

How does that SATA power interface work? Just an adapter from a normal PSU plug to the new SATA plug i'm guessing?

And lastly, up until now i've been able to get away with stock heatsink and fans for my CPUs, relying more on the fact that my Xaser III case has *counts* 7 fans.

Any recommendations on the type of CPU cooler to get? definately want something quiet, old friend got a thermaltake volcano something or other about a year ago and it sounded like he had a hair dryer strapped to his CPU, so yea... not wanting THAT! lol.

P.S.
right now, my system idles at around 31.2C (pentium 4 2.8Ghz 533Mhz, pre-HT). I know the prescott has mad heat issues, so exactly how bad is the temperature differential gonna be? are we talking 2-5C? 5-10C?

Anyways, thanx again for your help

________________
Logic
December 14, 2004 9:24:32 AM

MartinS

I don't know why I thought you were in the USA, but perhaps it's because your English is so good - actually better than most native English speakers!

You are right that PRB=1 allows the processor FSB ratio to be unlocked, as well as setting the motherboard voltage regulator. Intel certainly leave big gaps in the information about the characteristics of their processors. I suspect that the boxed 550J version will only be PRB=0, since introducing the 3.8GHz version Intel won't want users overclocking a "cheap" 3.4 to 3.6 or 3.8GHz. In effect they have re-designated the 550 as a "mainstream" part.

Your new PC, with its overclocking and water cooling will be quite a machine. It should last you 5 years, provided you don't load some new even more demanding software in 2 or 3 years!

As for me, I have now decided to abandon the searching and waiting for a 550J and go for a 560J, which are now available in the UK. It will give me all I want, except a lower power draw, but at the cost of an extra £80.
December 14, 2004 9:33:09 AM

LogicSequence

560J is the processor for you, but you must ensure that it is adequately cooled at 3.8GHz

As for memory, I believe DDR2 600 memory does not exist the next faster memory from DDR2 533 is DDR2 667. Corsair (XMS) and Crucial (Ballistix) both make similar 667. In the UK the Ballistix (BL6464AA664) is the cheaper of the two.

SATA drives can be used in RAID or non-RAID configurations and the system will boot from either. SATA does normally use different plugs (although some Maxtor SATA's used 4-pin Molex). However a system using the 925XE chipset is best powered from an ATX12V v2.0 power supply, which are not yet particularly common. This will have SATA connectors a 24pin plug and 2 12v rails. For example, Fortron (FSP) do a 400W and Hiper do a nice 480W.

As far as the DVD drive is concerned IDE will be fine, in fact I'm not sure who makes a SATA version yet.

Obviously it's the season for new system bulids! Good luck!
December 14, 2004 10:47:51 PM

Most prescott systems are reporting idle temps of 50 to 60c, so expect a major cpu temp rise. The scotties were designed to handle it. Many people have found the noise from the boxed fan to be annoying, zalman makes some very nice alternatives.
December 15, 2004 2:36:06 AM

"And lastly... New DVD-RW, should i get a SATA version or stick to IDE?"

Well, the SATA plextor is very expensive now and burner need only ATA33.... so unless they get really cheap or you want a "no messy cables" case, then SATA with it's smaller cable may help you.

but right now, I woud say, get an IDE one with round cable

-Always put the blame on you first, then on the hardware !!!
Anonymous
December 17, 2004 10:14:09 PM

I really can't tell. Usually i read a lot of reviews and tests when i want something. there are quite a few articles on the web which are comparing a whole bunch of coolers or whatever item you're looking for.

So... read, read and read. :) 
December 19, 2004 2:10:44 PM

Well, can anyone recommend a good CPU cooler (that's relatively quiet)? Something we know will work well to cool an OC'd P4 Prescott?
!