Memory FAQ

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Drisler

Gawd
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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.
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Noted...and added more Intel info.
 
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.
 
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.
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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.
 
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.
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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)
 
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.
 
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)
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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
 
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.
 
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.
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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.
 
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
 
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
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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.
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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.
 
hmm, I wasn't aware that intel boards allowed you to change memory timings either

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

oh well good work anyways

-Nutroid
 
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?
 
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
 
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
 
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
 
Originally posted by kevdog
this cat (drisler) deserves a new handle for this sticky:cool:
nice FAQ
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I just wanna get un-banned / un-KC'd at genmay.
M22 don't like me and i'm innocent of all charges :( ...help?
 
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?
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What did you do?
 
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
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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.
 
64bit + Capable Memory Benchmark

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
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Ive used this to verify that my dual Opterons memory (4GB) is properly configured (for 128bit interleaving)
 
wow 4 g now thats a lot. what do you play or run for so much memory?
 
Graphics and Animation Rendering (specifically Maya5)
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
 @ Workstation Planet
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."
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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!!!
 
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!!!
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Well, one is guaranteed to work, the other isn't.
 
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?
 
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.
 
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.
 
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
 
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.
 
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.
 
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.
 
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