Dell 6000/9300 FSB and RAM questions

[PerlAddict]

Okay, my problem goes a little deeper than just Dell laptops, in that I don't have much knowledge of how the whole Intel platform really handles FSB. I know it's quad-pumped, so while my DDR400, PC3200 ram in my AMD rig runs at an overall FSB of 400Mhz in my system, it would run at 800Mhz FSB in an Intel system. If I'm already wrong there, stop me now and get me on track. Regardless of the bus speed, the ram itself is running at 200Mhz in the BIOS for both systems, yes?

So my problem is that I've taken my limited knowledge of desktop Intel systems and not paid attention to the differences in laptop systems (nor do I have much knowledge of how the new Dothans with their 400/533 rated specs work).

I ordered a Dell 9300 last week for Dad. 1.6Ghz Dothan @ 533Mhz FSB, and it comes with 1 stick of DDR2 ram at 533Mhz. Now, I was assuming the 533Mhz was the DDR rating, meaning the ram would be PC4200 DDR533 speeds, or actually running at ~ 266Mhz in the BIOS.

I also ordered my brother a laptop - a Dell 6000, 1.86Ghz @ 533Mhz (did this before I knew about the pin mod to get Dells up to 2.13Ghz buying a 1.6Ghz/400Mhz Dothan from a third-party, but oh well ... he probably needs the warranty intact anyway).

Anywho, both systems and invoices say the processor runs at 533Mhz, but the 6000 invoice says it has 1 stick of 400Mhz ram instead of 533Mhz. Naturally, I was thinking, huh?

Then I got wondering - is that 533Mhz actually the OVERALL quad-pumped bus? Meaning the ram is actually only running @ 133Mhz, or DDR266 speeds?

Which would also mean that PC3200 or PC4200 would both be unclocked to run on the laptop, and you could actually run this system off PC2700, DDR266 speed ram? (DDR2, of course. Not regular DDR).

The reason this is so important for me to get figured out is because I bought 2x512MB of Kingston PC3200 ram for the 6000, and was planning on taking the 256MB stick that it came with and sticking it in Dad's 9300 to give it 2x256MB.

But since the invoices said the stick in the 9300 is a 533Mhz stick, and the one in the 6000 is a 400Mhz stick, I didn't want to run into any compatability issues sticking them both in the same system.

If I'm assuming correctly, though, they'll only be running at 133Mhz anyway, with the overall system bus running at 533Mhz, so it won't matter what the ram speeds are as long as they can run DDR266 speeds at the same timings. (which kind of blows my mind, because that just seems so slow anymore ... but then again, I've never dealt with laptops, so I'm likely comparing apples to oranges).

Did any of that make sense? Help an AMD fella out - I feel as lost as a baby in a boob factory.

 

[PerlAddict]

I should also probably add that I am clueless when it comes to memory dividers for the most part, so if that's part of the equation here in how these laptops FSB is figured up, be sure to make a note of it. =)

 

[ozzlo]

The memmory is eigther on an insane multiplier 4/2 or it's running 1 to 1 quad pumped like the bus. It is DDR 2 after all i guess it's possible it's quad pumped. The ram actually runs at 533mhz in the 9300 (i just checked with sisoftsandra) the insprion 6000 is probbably using a 3/4 ram/bus divider the 6000 afterall is supposed to be a economy model.


the 533 stick would work in the system that has the 400 stick ( it would just downclock) but the 400 stick will not work in the system that has the 533 (unless is can hold a 30% oc that is )

 

[PerlAddict]

Is that just a guess? Because this article on pin-modding a Dell to overclock it leads me to believe otherwise - that the ram actually DOES run at 100Mhz and 133Mhz, which would seem to mean you only need PC2700 speed ram to run within the rated FSB specs:

http://www2.ijib.com:1337/phpbb/viewtopic.php?t=3

 

[ozzlo]

ok after a little research.... yes you can put pc 2100 in there instead of pc 4300 but.......


1. WHY WOULD YOU WANT TO DO THAT???


2. It must be 200 pin modules NOT 172 pin modules


3. The dell bios may not support it


4. WHY WOULD YOU WANT TO DO THAT???


I'm pretty much positive now that ddr 2 is quad pumped like the FSB is, so in theory a normal ddr stick would work but you would only be able to obtain a speed of pc 266 because the memmory divisor is locked down in 1:1 ratio. and on the i6000 you will only be able to obtain a speed of pc 1600(ddr 200)....... That would definatelly be a step in the backwards direction.



my last post i was about 75% positive now I'm about 97% positive.



so yes you might be able to do it but the ram divisor is locked so you would be stuck with crappy speeds

 

[PerlAddict]

Never said anything about PC2100 or PC4300 in concern to the 533Mhz bus. No offense, but I'm looking for someone who is already familiar with the system and knows the answer.

These modules need to be DD2, no if's, and's, or but's about it. And with a quad-pumped bus of 533Mhz (neither of these systems is running 400Mhz FSB, they're both at 533Mhz), any DDR2 that can run 133Mhz (or PC2700 speeds) should suffice, meaning PC3200 and PC4200 are being underclocked (ie, you are getting no performance gain from using PC4200 ram over using PC2700 ram unless you are actually overclocking the system bus itself). Sticking PC2700 speed ram would likely be cheaper for an upgrade, to answer the "why would you want to do that" question, and since it's going to run at the same speed as a PC4200 stick you could buy and stick in there, you're not trading off performance for budget.

I'm mostly looking for someone knowledgable with these systems to verify whether or not this is correct. Thanks for trying to help, though. I do appreciate it.

 

[PerlAddict]

To update this myself and answer my own question - I stuck one PC3200 256MB stick and one PC4200 256MB stick in the 9300 today. BIOS showed the ram as "400Mhz," and everything booted up fine. Didn't get a chance to load up CPU-Z to see what it was reporting the FSB bus as, but the processor still reported as 1.6Ghz in the Control Panel, with an actually running speed (since it was under no load) of just under 800Mhz, which is the floor.

 

[ozzlo]

uhhh actually sisoft sandra is reporting that the ram is running at pc 4300(266mhz x2=533mhz). si soft is reporting a ram divisor of 2/1 which is making the ram run at 4x the bus speed thus the ram modules are running at their rated speed of pc 4200. I've been trying to explain that. you might want to verify that with cpu-z. I don't have the program installed.

scuse me 4300 was a typo i meant 4200.

 

[PerlAddict]

Did you look at the site I posted above? CPU-Z verifies a FSB of 133Mhz with a multiplier of 15. And Intel is quad-pumped, so if you're figuring it as 533/2=266, then that's fine for an AMD setup, but if the final FSB is 533, then in this case you use 533/4, which is 133. The BUS is running at 533Mhz, yes. The ram itself is only running at 133Mhz, from what I've gathered.

PC4200 running at its full speed on an Intel quad-pumped system should end up at a final FSB of 1066Mhz, not 533Mhz.

 

[ozzlo]

NO!


THE RAM IS ON A 2/1 DIVISOR!!! So yes it is running at 533mhz


bus speed = 133mhz * 2/1 ram divisor = 266mhz * 2 (double data rate) = 533mhz



it's called a ram divisor instead of a multiplier because 99% of the time the ending result is less than 100% but this divisor gives 200% so technically it's a ram multiplier.


Just like the processor has a multiplier, the ram does too. I hope This can explain it better than in all my pevious posts. If not I hope sombody else can
notice I own the said system you are talking about.(see sig)


i completelly understand the 533/4 = 133mhz actual fsb thing,I've been a diehard intel fan for years

 

[PerlAddict]

So with the divider, should CPU-Z be reporting 266Mhz or 133Mhz for the ram's (not the bus) speed?

Sorry for any misunderstanding or lack of faith, but your first post you were "75% sure of your info" and your second you were "97% sure" and "pretty much positive," which basically said to me, "I am guessing based off general knowledge I have elsewhere and some stuff I read." Which is the exact same thing I'm doing. You're the one who said you weren't sure what you were talking about in the first place, so forgive me if I took anything else you posted with a grain of salt - hard not to.

You told me to check it with CPU-Z. CPU-Z shows 15 x 133 in the link I posted above, hence the confusion. And the post still doesn't make much sense to me, unless Intel's method of "quad-pumping" is simply to flip around a ram divider, which didn't seem that likely to me. And you listed the first number as "bus speed" - should that not be the ram speed instead? Which would be exactly what I was saying before, that the ram itself is only running 133Mhz (regardless of what the actual bus is running), meaning no performance gain between PC2100 (DDR266) and PC4200 (DDR533)?

Are you basing all this from what SiSoft Sandra is telling you?

 

[ozzlo]

READ THIS...
http://www.laptoplogic.com/reviews/dell/89/5/1/



I just downloaded cpu-z and it is only displaying 133mhz (I think the version we have has a bug which dosen't show the correct ram speed.) bolth sisoft sandra and memmory validator are showing 266mhz.(which is what it should say.)


I am more and more sure of my info because over the past few days we have been having this conversation I have been consulting with benchmarking programs and reading articles on the matter. I'm not just going to go on my instincts and blah blah blah for days on end, I'm going to make sure that what I am saying is right.

 

[PerlAddict]

That review provided zero useful information on ram speed, other than pointing out that the ram is running 133Mhz x 15 to reach the final speed. If that's the case, then the 915PM chipset isn't quad-pumped - which was part of my original question - and actually works like an AMD chipset where you have the ram's speed and then the bus speed of double that thanks to being able to read on the rising and falling edges of the cycle since it's DDR. Otherwise if it IS running quad pumped, and the ram IS running 266Mhz, then you're slowing the bus down before quad-pumping it back out, which I don't understand but seems to be the most plausible explanation, as you could just use low-speed, lower latency ram for cheaper and achieve the exact same final results with no memory dividers. Except I guess that you wouldn't be able to use DDR2, since they don't make modules that speed afaik. I'd load up CPU-Z and sandra, but I can't test anything until Monday, sadly, as the laptops are both at the office.

"I am more and more sure of my info because over the past few days" - Like I said again, I appreciate it, but I've been reading, too. I'm interested to hear someone who's 100% sure of his info upfront from his own experiences.

And saying you think CPU-Z is bugged and SiSoft is right could just as easily work the other way around without proof of bugs.

Keep in mind the authenticity of articles, too. I recently picked up a PC modders magazine that stated the FX-53 runs at 100Mhz x 22 for the multipler, which is complete and utter crap.

 

[ozzlo]

if your in a hurry page 252 of the intel white papers will sum it up!!!
ftp://download.intel.com/design/mob...ts/30526401.pdf



Well I rebooted the computer and cpu-z says 266mhz which is what it is supposed to say.


if you won't accept an article then you will have to take it straight from INTEL.
http://www.intel.com/products/chipsets/915pm/index.htm
intel is showing support for only 400 (200mhz x2), 533 (266 x2) mhz 200 PIN DDR 2 memmory OR 333 (166mhz x 2) 200pin ddr1 memmory with the chipset. all of theese frequencies are obtained via the ram divisor/multiplier.





page 18 describes the 9300 chipset and ram that can be used on it. the bottom of page 252 is all you need to see to figure this wole mess out.
ftp://download.intel.com/design/mobile/datashts/30526401.pdf



i also have a thread over at the notebook forums also talking about exactly what we are talking about.
http://www.notebookforums.com/showthread.php?t=85006&highlight=533+ram


Here's a thread about cpu-z reporting a faulty frequency post # 5 sums it up quite nicelly
http://www.notebookforums.com/showthread.php?t=77203&highlight=533+ram





so according to the white papers the motherboard has it's own ram clock generator which is independent of the fsb but will not clock the ram faster than the fsb. (see page 252 of whitepapers) depending on what memmory/fsb setup you have... so then the following combinations are possible. obviously the 9300 runs at 533 so only the listings with 533 bus are imporntant to you but I threw in the 400 fsb combinations in for reference.


DDR 333
400mhz fsb (100 mhz actual) > 166 ram clock used = ddr 333

DDR 333
533mhz fsb (133mhz actual) > 166 ram clock used = ddr 333



DDR2 400
400mhz fsb (100 mhz actual) > 200 ram clock used = ddr2 400

ddr2 400
533mhz fsb (133mhz actual) > 200 ram clock used = ddr2 400



ddr2 533
400mhz fsb (100mhz actual) ram bus cannot exceed fsb thus ram is underclocked! 100 > 200mhz ram clock = ddr2 400.

ddr2 533
533mhz fsb (133mhz actual) > 266 ram clock used = ddr2 533


i can't spell it out for you any more, Those are the only combinations supported by intel for this chipset.

And by the way I'm 110% positive and have referenced 5 sources (2 of them very credible) that stated mostly the same information that I have been trying to explain since my first reply. The only thing I have found that I was inaccurate on is that the chipset supports ddr 2700 instead of 2100 and that the chipset has it's own independent ram speed generator which (in most cases does not depend on the bus speed) instead of a multiplier which I have been saying but it's still true ddr 533!



I would be most interested to see what material you have read

 

[PerlAddict]

Thanks for all the hard work, man. I appreciate it. We actually busted apart some benches last night and found that it's just a simple divider (like you posted this last time, and I suggested before). Used my buddy's Dell, and his runs a bus speed of 100Mhz and a ram speed of 133Mhz with a 3:4 divider, and these are running a 1:2 divider. Which seems silly to me to do, but I suppose with DDR2 not being made at the lower speeds the bus actually runs at, and the 915PM chipset not supporting higher FSB, to marry the two together on the same platform it's all they can do since they can't run 1:1.

Thanks for all the effort, bro.

 

[ozzlo]

no problem... it seemed like you really needed to know