Memory FAQ

[Drisler]

Originally posted by burningrave101
*On a side note i would just like to say that Intel platforms benefit from the tight timings the same as AMD machines do and that there is no benefit in running PC4000+ over PC3500 with tight timings on an 865/875 chipset board. On the other hand, on an 848 chipset board without dual channel abilities, the huge increase in bandwidth benefits more. In order to see the benefits of low latency memory over high speed bandwidth you have to have dual channel enabled and run with aggresive timings such as 2-2-2-6 or 2-2-2-5.

Noted...and added more Intel info.

[clreinstein]

Drisler could you elaborate more. Ive got an 845 board and am interested since it lacks dual channel and any more speed I can get out of it the better.

[burningrave101]

Originally posted by clreinstein
Drisler could you elaborate more. Ive got an 845 board and am interested since it lacks dual channel and any more speed I can get out of it the better.

If your talking about the motherboard in your sig then anything faster then PC2100 isn't going to benefit you. Your 2.4b processor is 533FSB (133MHz). I see that your currently using PC2700. The reason anything over PC2100 wont benefit you is because your motherboard is an Intel board right? Well you can't overclock a processor on one of those.

[yoda634]

NICE FAQ. :D

[snowwie]

Originally posted by burningrave101
If your talking about the motherboard in your sig then anything faster then PC2100 isn't going to benefit you. Your 2.4b processor is 533FSB (133MHz). I see that your currently using PC2700. The reason anything over PC2100 wont benefit you is because your motherboard is an Intel board right? Well you can't overclock a processor on one of those.

yes, but 845PE chipsets support a memory divider (x2.5) to allow ddr333 speeds even when the fsb is 133. on the 845 chipset, you want all the bandwidth you can get, so go for the highest divider you mobo supports. There is a pin trick to make your mobo think your 533MHz cpu is a 400MHz, and thus enable an even higher divider (x2.66) to get ddr356 speeds. No overclocking necessary.

Unfortunately I forget where this pin trick is located, so it would require a bit of googling (when will the damn search come back)

[clreinstein]

Yeah its a pe board. Im running pc2700 because thats what the school installed. When you think of the pin trick let me know or if they ever enable the search feature.

[snowwie]

http://www.thenakedreview.com/forums/showthread.php?t=258

heh, first link from google
not as hard as I thought it would be

[burningrave101]

Originally posted by snowwie
yes, but 845PE chipsets support a memory divider (x2.5) to allow ddr333 speeds even when the fsb is 133. on the 845 chipset, you want all the bandwidth you can get, so go for the highest divider you mobo supports. There is a pin trick to make your mobo think your 533MHz cpu is a 400MHz, and thus enable an even higher divider (x2.66) to get ddr356 speeds. No overclocking necessary.

Unfortunately I forget where this pin trick is located, so it would require a bit of googling (when will the damn search come back)

Yes but if you will look in his sig he has an Intel based motherboard so he can't change the divider.

Also is this the pin trick link you are looking for :)?

http://www.madshrimps.be/?action=gethowto&howtoID=32

[clreinstein]

Ok i looked at the links and they each show a trick but what do you use to bridge the two pins?? Someone mentioned rear defrost repair paint.

[burningrave101]

Originally posted by clreinstein
Ok i looked at the links and they each show a trick but what do you use to bridge the two pins?? Someone mentioned rear defrost repair paint.

Yea but dude can you even adjust the dividers on your 845PE Intel board? Because i was under the assumption you couldn't overclock and you can't change the dividers.

[snowwie]

of course the intel board will let him change the dividers

because even the intel board supports ddr266 for 400mhz chips and ddr333 for 533mhz chips

[burningrave101]

Originally posted by snowwie
of course the intel board will let him change the dividers

because even the intel board supports ddr266 for 400mhz chips and ddr333 for 533mhz chips

As every other product from Intel, the D845PESV mainboard has no means for CPU overclocking. You can't modify any frequencies or voltages in D845PESV.

This mainboard offers options for memory configuration, though. BIOS Setup allows adjusting the memory frequency (DDR266/DDR333) and typical timings, such as: CAS Latency, RAS to CAS Delay, RAS Precharge Delay and Active to Precharge Delay. We should acknowledge that it is certainly great progress, as not so long ago Intel mainboards didn't allow adjusting any memory parameters and used SPD information for memory configuration.

I see now that it was only the older Intel boards that wouldn't allow memory configuration changes. This is nice to know because after asking a couple other people about it and them saying the same thing i was convinced you couldn't change anything like that in the BIOS of Intel branded boards :).

In this case it would be called a memory multiplier instead of a divider i would guess.

[snowwie]

hmm, I wasn't aware that intel boards allowed you to change memory timings either

progress indeed

[nutroid]

have i read this somewhere else... im sure i have :S

oh well good work anyways

-Nutroid

[Drisler]

have i read this somewhere else... im sure i have :S

oh well good work anyways

-Nutroid

You probably have..
I got it up in another forum.

[n0lram]

very handy faq answered all my questions thanks!

[TwiceSliced]

Here's a question: Is there any software that will test the integrity of my RAM? For example, a recent installation of Windows 98 SE resulted in a "Windows Protection Error", which turned out to be cause by one bad 64MB stick of RAM... Is there a way to test for these kinds of flaws?

[Phoenix86]

http://www.memtest86.com

It is your memory testing friend.

[Keith130]

Great FAQ i learnt a lot, I found this on the crucial website today, i know some on has posted about RAM and windows but this is what crucial says :

Windows 95: 2GB
Windows 98: 4GB
Windows 98SE: 4GB
Windows ME: 4GB
Windows NT: 4GB
Windows 2000 Professional: 4GB
Windows 2000 Advanced Server: 4GB or 8GB with PAE enabled
Windows 2000 Datacenter Server: 4GB or 64GB with PAE enabled
Windows XP Home: 4GB
Windows XP Professional: 4GB

[snowwie]

chipset is usually the limiting factor before the OS

i875/865 chipsets can do 4GB max, most other cheaper desktop chipsets do no more than 2GB

[Bobzworld]

wow, some nice work here, thanks

[mikieboy]

4GB with windoze 98se?
lol
remember seeing an article years ago (think it was in pcw) which showed a large drop off in performance with win98se if u added more than 256MB of ram
in fact one of my first ever attempts at benchmarking was to see if a util called cacheman would improve the performance of my 512MB equipped 440bx. it seemed to improve things though lookin back i dont think i was creating the strongest evidence ;p
i would never go above 1/2 gig on non-NT5+ win
however for 2k and newer the limiter will be your mobo's mem controller
-my 6yr old daughter runs 2gigs of ddr400-mushkin level 2 on her XPsp1 i875 box

[Drisler]

Originally posted by mikieboy
-my 6yr old daughter runs 2gigs of ddr400-mushkin level 2 on her XPsp1 i875 box

:eek:

[kevdog]

this cat (drisler) deserves a new handle for this sticky:cool:
nice FAQ

[Drisler]

Originally posted by kevdog
this cat (drisler) deserves a new handle for this sticky:cool:
nice FAQ

I just wanna get un-banned / un-KC'd at genmay.
M22 don't like me and i'm innocent of all charges :( ...help?

[lopoetve]

Originally posted by Drisler
I just wanna get un-banned / un-KC'd at genmay.
M22 don't like me and i'm innocent of all charges :( ...help?

What did you do?

[lopoetve]

Originally posted by mikieboy
4GB with windoze 98se?
lol
remember seeing an article years ago (think it was in pcw) which showed a large drop off in performance with win98se if u added more than 256MB of ram
in fact one of my first ever attempts at benchmarking was to see if a util called cacheman would improve the performance of my 512MB equipped 440bx. it seemed to improve things though lookin back i dont think i was creating the strongest evidence ;p
i would never go above 1/2 gig on non-NT5+ win
however for 2k and newer the limiter will be your mobo's mem controller
-my 6yr old daughter runs 2gigs of ddr400-mushkin level 2 on her XPsp1 i875 box

You are correct. Due to a limitation of the addressing modes, 95/98 have issues with ram > 256, which causes a large performance drop-off.

[Drisler]

Originally posted by lopoetve
What did you do?

Dope account :(
My friend signed up..posted. We're both on the same connection. :rolleyes:

[Ice Czar]

64bit + Capable Memory Benchmark

STREAM (http://www.cs.virginia.edu/stream/) Sustainable Memory Bandwidth in High Performance Computers

What is STREAM?
The STREAM benchmark is a simple synthetic benchmark program that measures sustainable memory bandwidth (in MB/s) and the corresponding computation rate for simple vector kernels


Ive used this to verify that my dual Opterons memory (4GB) is properly configured (for 128bit interleaving)

[DRJ1014]

wow 4 g now thats a lot. what do you play or run for so much memory?

[Ice Czar]

Graphics and Animation Rendering (specifically Maya5 (http://www.alias.com/eng/products-services/maya/maya_complete/index.shtml))
I'll be doubling that too (the board can support 16GB, but has only 8 slots and required ECC and Registered)

Since this is a Memory FAQ thought Id add this

Breaking Through the 2 GB Memory Ceiling
(http://www.workstationplanet.com/features/article.php/3294451) @ Workstation Planet (http://www.workstationplanet.com/index.php)
by Jon Halpin Jan 1, 2004

Excerpts:
"With CPU clock-rates heading towards 4 GHz and beyond, the top of the line 32-bit processors found in most PCs these days are fast enough to tear through intense simulations, modeling, and data mining tasks. These chips, however, and to a large degree the entire x486 architecture, are limited because they can deliver only 2GB of RAM per application. Although that is more than enough memory for the average computer user, the average workstation user requires more.

Caching large databases, working with large 2D image files, modeling building plans in a CAD program, rendering complex machinery in an MCAD program, and running weather simulations all require the manipulation of large files in real time. And that often requires more memory than a 32-bit system can deliver.

On a 32-bit system, any given application will be limited to an allocation of 2GB of RAM, and the CPU limits the amount of RAM in the system to 4GB. This doesn't mean that a workstation with 4GB of RAM is always going to have 2GB going to waste. This 2GB limit applies to the resources that can be drawn by any one application. With 4GB, two different applications could crank through operations with 2GB of RAM each with the swap space never getting touched. Still, many workstation applications require more than 2GB to efficiently complete a single task.

The 64-bit Solution
The latest 64-bit chips, such as AMD's Athlon 64 and Intel's Itanium 2, have twice the memory registers of a 32-bit chip, but the total memory that can be accessed is much more than double. A 32-bit processor can access up to 4.3 billion memory addresses for a total of about 4GB of physical memory. A 64-bit processor could conceivably access over 18 petabytes of physical memory. If you are sorting a database with terabytes of information, than 64-bit addressing can make a big difference

Some applications are limited to 2GB even on 64-bit systems. Adobe's Photoshop has a 2GB RAM limit and Adobe has no plans of increasing it, even though Apple's latest operating system supports 64-bit extensions; Adobe says 2GB is plenty for the image editor's functions. Plus, using a Power Mac G5 with 4GB of RAM does enable users to work in Photoshop to the limits of its RAM allocation while, in the background, Final Cut Pro works steadily through a file conversion without impacting the speed of Photoshop.

If you need to manipulate large files or work with models in excess of 2GB, migrating to a 64-bit processor and operating system is essential. And with a bunch of 64-bit chips reaching the market, a host of 64-bit-ready Linux distributions, and a growing number of off-the-shelf applications, it is increasingly affordable to break the 2GB memory ceiling."

[VaniLLa]

I'm still unsure of whether I should get 2*512 of generic/value pc3200 or to get 2*256 of Kingston HyperX pc3200??? They both come in at about the same price...Which will give me the best bang? I plan on getting a 2500 Barton and an NF7-S. Any suggestions?

Thx for the great post! It really helped out a newb like me!!!

[lopoetve]

Originally posted by VaniLLa
I'm still unsure of whether I should get 2*512 of generic/value pc3200 or to get 2*256 of Kingston HyperX pc3200??? They both come in at about the same price...Which will give me the best bang? I plan on getting a 2500 Barton and an NF7-S. Any suggestions?

Thx for the great post! It really helped out a newb like me!!!

Well, one is guaranteed to work, the other isn't.

[VaniLLa]

Good point! :D

wait...actaully the generic ram also has a lifetime warrenty, probably from the retailer, and they're pretty dependable.

www.cbit.ca

I just want to know if quality 2*256 of pc3200 will preform better than 2*512 of generic?

[Phoenix86]

99% of the time more RAM is better (faster overall system) than faster RAM. The only time where it itsn't is when the lesser amt of faster RAM is enough (yes you can have enough RAM). Since you would likely make use fo the difference between 512MB and 1GB I would go with the 1GB.

[lopoetve]

With the number of experiences that I have had, I won't buy anything that isn't Crucial, Corsair, Mushkin, or Kingston. Ever.

You don't really have any worries with those guys. I've never had a problem. Generic, well... half the time, it just isn't really compatible. It's the cause of MANY a hardship here. Trying to debug a problem, only to have it be slightly flakey ram...

Speed wise, the 1gb is faster. Stability wise, and peace of mind wise, I'd get Crucial or something else. Even Kingston ValueRAM. Just not generic. I won't buy generic any more. I don't care HOW cheap it is.

[kv12482]

I'm trying to add RAM to a friends computer (dell dimension 2400) and the dell site says that it comes with "Shared DDR SDRAM." What does that mean? And can I just use DDR?

Thanks

[Phoenix86]

That means the your machine has "on-board video," it doesn't have dedicated RAM, so it's leaching from the system RAM. If you have 256 RAM and 32 MB video, only 224 is used for system memory, the video chip gets the rest.

To answer your question, yes, you can just use normal DDR, but integrated video is a major bottleneck for many applications. You may want to start a new thread and post what your upgrading (model numbers and such) and why (want to run XYZ game/app). That way we can get more detailed info to you.

[D14JEFF]

a friend has a stick of 256 pc 2700 that is a simm(chips on one side only).can she add a 512 stick of pc 2700 dimm (chips on both sides and will she have issues if she does?ive seen issues using simm and dimm pc 133 ram but didnt know if the same problem exhist with ddr ram.she either has an asus or abit board.thanks.

[D14JEFF]

a friend has a stick of 256 pc 2700 that is a simm(chips on one side only).can she add a 512 stick of pc 2700 dimm (chips on both sides and will she have issues if she does?ive seen issues using simm and dimm pc 133 ram but didnt know if the same problem exhist with ddr ram.she either has an asus or abit board.thanks.

[rive22]

wow thanks for the info man. i've gone from a ram noob to a ram pro, as long as i can remember everything. :D I can't wait to start trying different tricks with my ram now. these stickies rule!

[lopoetve]

Originally posted by D14JEFF
a friend has a stick of 256 pc 2700 that is a simm(chips on one side only).can she add a 512 stick of pc 2700 dimm (chips on both sides and will she have issues if she does?ive seen issues using simm and dimm pc 133 ram but didnt know if the same problem exhist with ddr ram.she either has an asus or abit board.thanks.

You've got your terms slightly off. You're talking about dual sided and single sided memory. A simm/dimm is different.

Memory banks: Where the memory goes (lol), and the way the chips are divided up in the addressing/hardware scheme. A full disclosure would take too much time.

SIMM: Single Inline Memory Module. These are the older type of memory, and had to be installed in PAIRS to make the bank full and functional (similar to the way RIMMs are now). Came in single sided and double sided. Haven't been used since the PII.

DIMM: Dual Inline Memory Module. These, by their design, have both halves of the bank on them. Thus, you only have to install them singly. They fill the entire bank on their own.

It's early, and I was out late... hope this makes sence.

As for your question, maybe, maybe not. I would buy the same kind of stick as you have installed (same brand/ratings), and it is almost guaranteed to work.

[zupadupa]

THUMBS UP to all that made this sitcky possible.... man I LOVE SITCKIES. Some really good an useful info here.

Anyone have any idea when DDR-II is comming?

[lopoetve]

Originally posted by zupadupa
THUMBS UP to all that made this sitcky possible.... man I LOVE SITCKIES. Some really good an useful info here.

Anyone have any idea when DDR-II is comming?

It's here, sorta. You can buy the modules. Just mega expensive. And I don't think that there are any consumer boards that will take them, yet.

[mayakindaguy]

I currently have 4x512 PC3200 and according to this article having all slots filled dramatically decreases performance even to the point where 2x512 performs better realtime compared to fully populated 4x512. Just wondering if this article has any credence.
thanks.

http://firingsquad.com/hardware/building_gaming_opteron_2003_Part2/page14.asp

So would having simply 2x512 of the Mushkin 2-2-2 special be better than 4x512 of comparable RAM. The article also didn't state whether this was truly applicable with higherend apps when say around 2gb was being eaten up and having 1gb would cause swapping. hmmmm any ideas?

[bobsaget]

Originally posted by mayakindaguy
I currently have 4x512 PC3200 and according to this article having all slots filled dramatically decreases performance even to the point where 2x512 performs better realtime compared to fully populated 4x512. Just wondering if this article has any credence.
thanks.

http://firingsquad.com/hardware/building_gaming_opteron_2003_Part2/page14.asp

So would having simply 2x512 of the Mushkin 2-2-2 special be better than 4x512 of comparable RAM. The article also didn't state whether this was truly applicable with higherend apps when say around 2gb was being eaten up and having 1gb would cause swapping. hmmmm any ideas?


Since you have four slots, why not 3x512?

[mayakindaguy]

no dual channel, I guess. Since I'm on an Intel rig.

[bobsaget]

oh yeah, damn. That will hurt you on a p4 system.

[davidj]

With all of the conflicting info concerning how much ram is better. Does anyone have the definitive answer??????????


According to Anandtech, 4 populated slots give better performance than 2 for the P4.

http://www.anandtech.com/memory/showdoc.html?i=1839&p=8

Conclusion-
If you plan to run DDR400 as your base memory speed with an 800FSB processor, your best memory performance will clearly be with four matched double-sided DIMMs. Our tests, confirmed by Intel.

White Papers, show these configurations ranked from fastest to slowest performance on an Intel 875 Canterwood or 865 Springledale chipset motherboard.



FSB Overclocking with 1, 2, and 4 DIMMs

Since we have established that the best performance at DDR400 or above (1:1) is with four DIMMs, it is natural to ask whether there is a downside to running four DIMMs instead of two or even one DIMM.

http://www.anandtech.com/memory/showdoc.html?i=1839&p=7

Despite the slightly lower overclock possible with four DIMMs, the best 1:1 performance is still with four DIMMs. For example, DDR516 using four DIMMs out-performs DDR530 with two DIMMs –since the four DIMMs are about 7% to 10% higher in UNBuffered memory performance.


While four DIMMs do not overclock quite as well as two DIMMs on an 875/865 board, we confirmed that the added memory bandwidth more than makes up for the slightly lower overclock with four double-sided DIMMs.




The first page to this article "Searching for the Memory Holy Grail: Part 1.

http://www.anandtech.com/memory/showdoc.html?i=1839:confused:

[mayakindaguy]

good info, but either Anandtech has to be wrong or Firing Squad does. It is weird how their tests results came out contradictory and I believe that the issue as to whether 4 occupied slots decreases or increases performance has been an unresolved issue, as far as I'm concerned.

I also didn't quite understand why the Firingsquard article said they used XMS for their benchs and then at the last sentence of the first paragraph of the last page stated that 2.8 with better memory can outperform a 3.0 in some benchmarks. Then they go on to say that one should note that they weren't using bottom of the line memory;they were using Crucial. (Where or when Crucial memory came up in the test setup I don't remember reading prior to the Conclusion page).

The Firingsquad article also states that Intel deals with increased number of memory banks by slowing down the latency. I personally have not tested this increased latency theory and frankly do not know how, but I have never noticed a sudden change in the cpu-z readings when using all four banks. I no longer have 4x512 dimms and have switched down to 2x512 of lower latency Mushkin RAM to be ugraded as needed. Unfortunately, this does not allow for my own further personal testing on the matter and has left me without a definitive resolution to the issue at hand.

oooh, I'm a Limp Gawd now.:D The word limp does not quite sound so appealing I might add.

[Phoenix86]

OK, you posted that firingsquad link in another thread, and this is just a cut and paste from my reply to the first post.

That article is an interesting read. Please notice this from the article, in bold. "extra memory can reduce system performance if it is unused."

Let me ask you this, do you think those benchies used 2GB? I doubt it. If they did, you would see a major performance increase in the 2GB vs 1GB because the latter setup would be swapping out to the page file.

Another thing, they are draw bad conclusions based on skewed testing. I wouldn't put too much faith in what your seeing. For example, they show you how ~bad~ it is to go from 1GB to 1.5GB on an AMD setup. Then they show you a memory bandwidth chart. Well, that mobo is DC capable, when they go to 1.5GB they are no longer in DC mode, if I recall correctly, and that will cut the memory bandwidth in 1/2, which it does... OK, so how does that affect performance? VERY LITTLE on that system. DC on an AMD setup yeilds ~3% increase. So the added bandwitdh isn't even used, so if it's cut in 1/2 who cares?

[ChingChang]

hmm I can only see 3 pages of replies. Can anyone see more?

[DaveX]

Yeah only 3 pages...what happened to the FAQ?

[ChingChang]

If this is the same FAQ as the one that was in the general forum a month ago, I have it saved in a word document if needed.

[Ice Czar]

some of the FAQs got wacked in the switchover
Im rebuilding a few already
ChingChang thanx for the offer, B.B.S. should have a backup of it as well as the mod of General Hardware, but if for some reason he misplaced it
we'll be in touch :p

[ChingChang]

ahh ok, that would explain why some of the other stickies are missing the beginning part :)

[Drisler]

I've got a copy with all the vb tags. Will repost when I get home.

[Mcseiam]

Drisler, I have rebuilt your previous FAQ and stickied it - this thread will now be cut loose.


Thanks again for the excellent FAQ ;)

[Lord of Shadows]

I personally dont know anything about DDR-2 other than what I've read and according to anandtech, (http://www.anandtech.com/memory/showdoc.html?i=1977) DDR-2 sends twice as much prefetch (whatever that is) than DDR, and can equal the max bandwidth of DDR with half the frequency, much like the QDR you mentioned.

And I really wouldnt acclaim DDR2 just yet, I dont think its all that great of an investment as of right now.

Great FAQ btw, learned a few new tricks, but you forgot to mention (Or possibly I missed it) the whole amd64's (old socket) dependence on registered dimms. And explaining what registered ram is, its effect(affect?) on latency, and about ECC and its ability to correct 1-bit soft errors and flag 2-bit soft errors.

Oh yeah, maybe this is best fitted for a video card FAQ but you should explain about what AGP aperture is, many people with say 512mb of ram set this to as high as it goes (on most boards its 256mb) effectively giving 256mb more mb to their gfx and halfing their total ram for pretty much no performance gain.

[Mcseiam]

Please use the new and improved FAQ stickied at the top of the forum