Can I use PC3200 in my PC2100 System?

[XxTRAINxX]

I have an IBM Netvista A30 (8315-42U) which requires PC2100 - 266MHz CL2.5 DIMMs. These things are quite expensive so I was wondering if I could use PC3200 DIMMs which "should" be backward compatible. I read something in the forums about the SPD not supporting 266MHz systems any longer but I thought I would see if that's true for this particular system.

 

I was thinking about picking up two of these:

VS512MB400 - PC3200

 

Will this work in this 266MHz system?

[XxTRAINxX]

Does anyone know if this is possible? I tried to do some research and I get conflicting answers.

 

C.r.u.c.i.a.l says its not a problem:

http://www.c.r.u.c.i.a.l.com/library/memory_speeds.asp

PC3200 is backward-compatible for PC1600, PC2100, and PC2700

 

Notice they don't say "may be compatible" but rather, "...IS backward compatible"

 

But the RAM Guys says is may be a problem:

http://www.houseofhelp.com/forums/showthread.php?t=47771&highlight=ddr+backward+compatible

That’s not true with ever module. Many DDR400 modules made now will only support DDR333 or DDR400 in the SPD and if you put them in a system that only supports DDR266 it may not post.

 

And CMC_Savage on the forums says it will down clock NO PROBLEM:

http://www.houseofhelp.com/forums/showthread.php?t=38526&highlight=ddr+backward+compatible

It should clock down to 266Mhz no problem.

 

So.... Should I buy some of this memory or nay?

[Osage923]

ToXxTRAINxX,

 

I too would like the answer you pose for a different reason. But I think that in your case---a stick or two of corsiar vs512mb266 would be the better answer. I am pretty sure those modules are still made---and if they are compatible with your mobo---which the corsair site may list, they would be probably similarly priced and a less of a gamble for you.

 

And if nothing else---would probably offer better ram timings than 2.5-3-3-8 the vs512mb400 offers and may not downclock from if it works for you at all.

[RJLeong65]

In your case, it is better to hunt for PC2100 sticks of memory. The IBM NetVista is an OEM system, much like a Dell system; as such, it offers no provision at all whatsoever to manually set the memory speed, timings or voltage. Also, the NetVista, like other OEM systems, requires a stick of memory to have a valid SPD programming for DDR266 in order to even work at all - most current sticks of PC3200 memory from Corsair know only DDR400 and DDR333 operation (according to their SPDs), with no SPD programming at all for DDR266. And if any OEM system cannot find an SPD at all for the system's supported memory speed, the system simply will not POST.

 

By the way, the only official JEDEC reference set of timings for PC2100/DDR266 memory is CAS 2.5-3-3-6. Any other setting is considered "tweaking."

[RJLeong65]

I get conflicting answers.

 

C.r.u.c.i.a.l says its not a problem:

http://www.c.r.u.c.i.a.l.com/library/memory_speeds.asp

 

 

Notice they don't say "may be compatible" but rather, "...IS backward compatible"

 

But the RAM Guys says is may be a problem:

http://www.houseofhelp.com/forums/showthread.php?t=47771&highlight=ddr+backward+compatible

 

 

And CMC_Savage on the forums says it will down clock NO PROBLEM:

http://www.houseofhelp.com/forums/showthread.php?t=38526&highlight=ddr+backward+compatible

 

It's all up to the memory module manufacturer to implement SPD programmings for lower clock speeds. The JEDEC standard for PC3200/DDR400 memory only requires SPD programming for DDR400 speed. (Note that the official JEDEC specification mentions nothing at all whatsoever about compatibility with slower speeds, so it is assumed that support for the lower speeds in the SPDs is entirely optional.)

 

All of #######'s PC3200 memory modules have SPD-programmed timings for DDR400, DDR333, DDR266 and DDR200 speeds - which may be the reason for that company's claim on its website.

 

And what CMC_Savage said on these forums in regards to downclocking of higher-speed DDR memory is true - but only if the motherboard's BIOS also allows for full manual override of the SPD detection of the memory clock speed and latency timings. It will not work properly with OEM systems like the IBM NetVista systems (unless the said memory module has SPD-programmed timings for those systems' supported memory speeds), which are permanently fixed to always autodetect the modules' SPDs no matter what; those systems will either run in their molasses-slow fail-safe mode (with the highest available latencies, the slowest supported memory clock speed and all caching disabled) or fail to POST in those cases.

[Osage923]

Its all well and fine to have various theories, guesses, well reasoned it should do this in a IBM netvista system.

 

But the proof of the pudding is actually trying it---and you go past all theory to actual results.---which trumps theory every time. The problem of course is in the basic $100.00 gamble it entails.

 

And the OP is asking a highly specific question about one specific computer. When others, myself included, ask in the more general case regarding PC2100 limited Motherboards in general.--and how they are likely to behave if fed PC 3200 ram. And now thanks to a few posters we get the information that an OEM specific PC2100 motherboard like an IBM or a dell is likely to behave differently when fed pc3200 ram than a mobo marketed to the general public and similarly limited to pc2100.

 

The point I seek to get at is that SURELY IN THE HISTORY OF THE ENTIRE WORLD some people have ACTUALLY TRIED THE EXPERIMENT and have survived to tell the tale. While it would be a minor miracle if someone pops up

with results of the OP's actual mobo, but I find it hard to believe that multiple people have not actually tried the experiment on various PC2100 mobo's. And this is the power of forums in general---and I hope one or more of these people can weigh in to give their proof is in the pudding results.

[XxTRAINxX]

Thanks for all the suggestions and information on the topic. I know this system is not the normal system you find in these forums but I'm trying to get it up and running with at least 1GB of ram so I can set it up as server. The system was free so I am trying to spend as little money as possible but also stay reliable.

 

The PC2100 memory tends to run more expensive than the PC3200 which is why I wanted to know if PC3200 would work. That being said, I found the Corsair PC2100 on newegg for around the same price as the PC3200 so maybe its not that big of a deal. But, it would be better to purchase the PC3200 so I could use the memory in the future for faster systems.

 

I realize we are talking about minimal differences in money but again, the system was given to me free so I was trying to see if I could make something out of it. I really want to purchase the faster RAM so I could possibly reuse it in the future but I dont want to purchase the RAM and have it not work.

 

If the answer is "It might work but you won't know until you buy it", then I guess I will just grab the PC2100 and be done with it. Thanks to everyone for the input and assistance.

[Osage923]

To XxTrainxX,

 

For what its worth, there is now a post by someone with a similar IBM netvista system in the general section---but not your exact model---but something that likewise had a PC2100 board. And this person bought a single GB stick of corsair XMS PC3200, stuck it in his IBM, and as some predicted, the bios refused to even see the ram.

 

So he is stuck with almost $100.00 of ram he can't use. But if the corsair memory compatability page says a given model number of their ram will work with your system---me thinks corsair will stand behind that data regardless of where you buy the ram.

 

And also check zipzoomfly for prices---you might save a few bucks over the egg.---or use various shop bots to find the cheapest new prices.

[bluerangerA51]

I'm with you on:

 

"The PC2100 memory tends to run more expensive than the PC3200 which is why I wanted to know if PC3200 would work. ... But, it would be better to purchase the PC3200 so I could use the memory in the future for faster systems. .... I really want to purchase the faster RAM so I could possibly reuse it in the future but I dont want to purchase the RAM and have it not work."

 

That was my thought as I bought a stick of VS5512MB400C3 to add to a 256 MB PC2100 I already have installed. It didn't work together. The new stick didn't work well by itself either. My computer had a near death experience. (it reported seeing a white light which was probably my flashlight shinning into the case as I checked for loose connections:laughing: )

 

Belatedly I checked the BIOS settings and saw that there were 3 choices on the CL: CL2.0, CL2.5 and AUTO. This new memory is CL3 so I believe that had something to do with my problems. RAM GUY, could that be a problem? :confused: From this experience I would say be very careful about what will actually work with any board.

 

Unfortunately the MB info never mentioned CL requirments. :(:

 

The Corsair compatibility checker said it should have worked. :confused:

 

There is a ssslight possibility that something else happened to my motherboard or OS that was not directly related to this new memory. But I'm not going to try it again. I've got too much video work with deadlines that needs to be done using this computer this week! I'm going to opt for a safer memory upgrade even though I may not get to use it on another system.

[Osage923]

To bluerangerA51,

 

If you are stuck with that stick of vs512mb400c3, chew through your video work at whatever slow speed the 256 MB of ram will allow. Then budget some times and try cl2.5---for some strange reason--thats the setting that ram likes to use on my system---and it should handle 2.5-3-3-7 @pc2100 with total ease. Its running at PC3200 in my system with absolutely no errors.--the only difference is that I have the vs1gb400 which sends the c3 spd. Its the advantage of buying a high quality ram like corsair---the spd it send to the bios are very conservative. And those settings are the PC2700 settings for that ram anyway.

 

And by all means be willing to experiment---as long as you don't overvolt you will not hurt your system or your ram. You might try pulling the 256 MB stick out and putting in the vs512mb400c3 corsair---then reset your bios to those settings and boot it up. Believe me---even 512mb is a huge improvement over 256 MB---and with some luck and some bios tweaks you could get all 768 MB working and stable.

 

After all, what do you have to lose except some time. And don't panic if the first boot is a no boot--a few bios tweaks will usually remedy that. And I had to run through a bunch of trial and error settings bios settings before I got both error free and full memory bus speeds. And I was running two slightly different sticks of ram. But if your bios refuse to even see the vs512mb400c3 stick--you are doomed

and the stick simply won't work in your board.

 

Let memtest86 and cpu-z be your guides. Know what what you had before---and see what you can get now. You can go back to what you had if necessary.

[RAM GUY]

As Osage923 stated try Cas 2.5-3-3-7 or Cas 2-3-3-7 at 2.7 Volts and see if the system is stable with http://www.memtest.org.

[Osage923]

To bluerangerA51,

 

Since making my earlier post, I had a few additional random thoughts.

 

1. I recall another post on this forum where a stick of vs512mb400 was sending a pc2100 spd of 2-2-2-6@pc2100---but I am assuming this was an earlier manufactured stick and more modern sticks no longer send that spd. But that too becomes a possible setting and shows you have very good ram.

 

2. Another timing to try may be whatever your existing stick of 256 MB of pc2100 ram runs at---which cpu-z will show---but a common pc2100 speed

is 2.5-3-3-6. But let cpu-z be your guide. Then if the 512mb corsair will run at those speeds stable, you are almost certain to be able to add in the 256 MB module---which you know runs happy at that speed.---with ddr being far more tolerant than ddr2.

 

3. It would help to post what your system specs are. You may get lucky and find someone with exactly what you have---and then they can tell you what they did to get their system running right. Which may save you a ton of trial and error. Its simply the people power of forums.

[bluerangerA51]

Thanks guys for your posts.

 

I think the problem was that the chipset only accommodates the following ranges because the following are the only options available in manual settings:

 

CAS Latency: 2.0 or 2.5 (the RAM has a CAS3 - this is probably the first problem, I am pushing

the RAM past it's operating parameters by trying to make it operate in a shorter number of cycles as far as latency goes, isn't that right?) It seems to me that it just won't be able to respond in a shorter clock cycle time. In that case running a CAS2.5 RAM at CAS3 should work but not the reverse? Or does that change because this 400MHz Ram is downclocked to 266MHz for my slower system?

 

Precharge to Active: 2T or 3T ( I don't know where on the Corsair site this or the following information is available for the RAM)

 

Active to Precharge: 5T or 6T

 

Active to CMD: 2T or 3T

 

Burst length: 8QW or 4QW

 

Command Rate 2T or 1T

 

Frequency: Auto, 200Mhz or 266Mhz

 

There is no setting for voltage.

 

:idea: It would seem to me that if the RAM's parameters do not match in even ONE of the above available settings, it will not operate correctly since the North Bridge cannot supply the timing the RAM needs in order to read and write the data.

 

I may let a friend try this RAM in his computer since his takes CAS 3 and he is needing more RAM anyway. Without knowing the other timings needed by the RAM we will still be only guessing. He says the RAM is not listed as one that works with his system.

 

I am looking at another set of Corsair RAM, 2 sticks of 512MB and although they have a CAS2.5, one of the parameters, the 7T, does not match the choices available in my BIOS so I probably should not try it.

 

What do you think?

 

I'd like to try the cpu-z you mentioned if I can find it. But AFTER this video work gets done. At least I have 384 MB to work with.

 

Thanks for your input.:):

[Osage923]

To bluerangerA51,

 

I see from the corsair site, that you are indeed 100% correct and corsair did list

vs512mb400c3 as compatible with your system. Kinda putting corsair over a barrel in helping you get that ram working. But to let you know---the slower your memory bus runs---the tighter your ram timings can be---so that will easily run cl2.5 and maybe 2. Set command rate initially at 2T.---I'll let the ram guy recommend other setting---but just be willing and prepared for some trial and error also.---this is not all cut and dried science.

 

In terms of getting cpu-z---just google "cpu-z" without the quotes. Or google major geeks which I happened to visit today---and noted the latest cpu-z is up to ver. 1.4----with cpu-z being something like a 438 KB zip file---download and unzip to a directory. And then place a shortcut on your desktop. See what your existing memory is running at---and see if the vs512mb400c3 will run at those rates also is your best initial guess.

 

I also note the latest bios version is 1014-002 which may give you additional bios options---I also note you have 2 memory slots--on a mobo that can run a memory bus at pc1600 or pc2100---the mobo info is also very clear on how to jumper reset your bios which you may need to do.

 

But I assume you were running a stick of 256 mb ram and an additional stick of 128 mb ram---giving you 384 mb---and even 384 MB's would leave your system memory starved for video editing.

 

But were I trying to get your system running the vs512mb400c3 I would do the following.

 

1. Run Cpu-z---check your memory tab--and see what your existing stick of 256 MB is running at. Then I would power off the system--remove the 256 MB stick---and the 128 mb stick--and place the vs512mb400c3 in slot 1.

 

2. Then I would power on and immediately enter your bios and match those prior setting in the bios---and then power off.

 

3. I would then power back on with memtest86 in your first boot device--be it a floppy or a cd--and let the system boot into memtest86--and see if your computer memory runs error free---if not--power off and try another settings

until you get error free---and hopefully at pc2100 bus speeds. Then you can boot back into the OS---and with luck you can later add the other 256 MB stick and still have a stable system.

 

But the ram guy can give you better advice than I can.

[bluerangerA51]

Thanks Osage 923 for your advice there. I may get more adventurous with the computer next week after the video editing is done and use those two tools to see if any settings will work. Booting off a floppy sounds like a safer way of trying things out anyway that way memory problems won't mess up files written back to Windows settings or something.

 

I'll post back here next week and let you know what happened. It may help someone else too.

 

Thanks again.