4GB of Ram... Is it possible...

J

jack_r

Weaksauce
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Jul 20, 2004
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I'm looking to build a new computer for school/research with 4 Gb of ram. I'm doing large finite element calculations and having this much ram would significantly cut down on solving time. Has anyone had any luck building a PC with this much ram???

I'm not talking about a server board, or some super computer...because of the budget I have been given and my familiarity with Athlon's I am planning on building an Athlon 64 machine. I was thinking of using the popular MSI K8N Neo2 Platinum motherboard with an AMD64 3500+ (socket 939) processor. For ram I'm looking at using Corsair's TWINX2048-3200PT ram. These are 1Gb sticks of ram sold in matched pairs. I was planning on maxing out the board by using 4 sticks.

So... what do you think... will it post... will it be stable enough to run calculations which take hours? I figure ram timings aren't that important, and overclocking is out of the question... stability is the main factor. I would really appreciate hearing from anyone who has tried using this much ram.

As an addendum: I know about the ram addressing limitations of a 32 bit system... I plan to use Windows XP with the /3Gb switch until the 64 bit edition comes out... and if needed I'll use a 64 bit version of Linux
 
jack_r said:
I'm not talking about a server board, or some super computer...because of the budget I have been given and my familiarity with Athlon's I am planning on building an Athlon 64 machine.
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If you're on a budget, it must be fairly large if you're planning on dropping the cash down 4 gigs of matched DDR.
 
Here's what I'm thinking... for a budget of 2 grand... ordering from Monarch, Compusa, Best Buy, Outpost and Heatsink Factory...


AMD Athlon 64 3500+ Retail Box (Socket 939)
MSI K8N Neo 2 Platinum (socket 939)
CORSAIR XMS 2GB (1024MBx2) PC3200 (2 of these)
80 GB Seagate 7200 RPM ULTRA ATA
36.7 GB Western Digiral Raptor 10k RPM SATA (2 of these)
Radeon 9600 128MB DDR Ram
Antec Performance Series II (Model SX835II)
Antec True Power 550W ATX
Samsung 52X32X52X16 CD-RW + DVD ROM (8MB Cache)
Sony 1.44MB White Bezel
Microsoft Internet Keyboard
Click! Logitech USB/PS2 Mouse
Panaflo 80mm 24CFM 21dBA with 4 pin tail (5 of these)
 
I'd also look into ordering parts from newegg and gameve
 
ZePHyRaNTHeS said:
That's not his sig lol. He was listing what he wanted to buy.
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HAHAHA, Who reads the rules anyways :p

This a very hansome budget. And Damn! give me a problem that your doing in this math class, 4GBs is huge!
 
if you got a $2k budget, id spring for dual opties, and buy as much RAM as you can with the money left over. is your app multi-threaded?
of course, opties require that expensive bling bling RAM....:(
 
By the way, if you occupy all 4 dimm slots, your memory is going to be clocked slower. ie: if you get 4 gigs of ddr400 ram, it's going to clock down to ddr333 speeds.
 
Why would occupying all 4 dimm slots cause 333Mhz??? In a recent article on Anandtech (see link below) they mention running all 4 dimm slots on the MSI motherboard, I'm guessing with 512Mb per slot, and only needing to change the command rate, not FSB speed...

http://www.anandtech.com/mb/showdoc.aspx?i=2128&p=11

By the way... Ramguy (the expert over at corsair's website) mentioned the reduction to 333Mhz also...

I wonder how big of a hit I'd take running at 333Mhz vs 400Mhz...

A tech support guy at MSI seemed to think that there wouldn't be any problem running 4Gb at 400Mhz...
 
You've done your homework I must admit. I don't see any potential problems with your setup although that budget is probably going to be stretched tighter than Roseanne Bar's thong but it should be fine.
My only recomendation is don't skimp on the power supply. With that much RAM, limiting power fluxuations due to load are going to be critical. Get a high quality power supply rated for 450 Watt at least just to ensure you don't suffer from power overload issues.
 
I've got an Antec True Power 550W on order;-) And yes, I'm doing my homework on this one. Its the first computer that I've built at my new job... I don't want to ruin my rep:)

This to #9 mr. steel chicken. The program that I'm running is Ansys... and though it supports multiple processors, benchmarks that it only scales well on large unix based workstations (many processors, lots of ram and mega-bucks.)
 
The_Mage18 said:
I don't see any potential problems with your setup although that budget is probably going to be stretched tighter than Roseanne Bar's thong but it should be fine.
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Thats a truly, horrific thought. Shame on you.
 
firey-eyez said:
eh the new G5 has room for 8 gigs. you dont got shit on the G5 dual proc. :D
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well, except the fact that the opteron is faster. oh yeah and the tyan boards have a minimum of 8gb, some go all the way up to 32GB. oh yeah, and based upon price comparisions, cheaper too, so yeah, i guess that aint shit
 
The_Mage18 said:
budget is probably going to be stretched tighter than Roseanne Bar's thong but it should be fine.
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ROFLMAO!!!!

Does the memory haved to be in the matched sets like l337zax said? I thought that was just marketing BS.
 
ZePHyRaNTHeS said:
By the way, if you occupy all 4 dimm slots, your memory is going to be clocked slower. ie: if you get 4 gigs of ddr400 ram, it's going to clock down to ddr333 speeds.
Click to expand...

I think what he means is that the JEDEC spec dictates one unbuffered DIMM of DDR400, two of 333, and three of 266. Of course, that's on a per channel basis, but even then people have been able to get things to work above the specs. And registered DIMMs (Opteron land) provide the use of more high-speed DIMMs per channel.
 
I've looked at the dual opteron option and deemed it infeasible with my budget. For instance, 2 opteron 244's cost $600, a dual tyan 400mhz fsb board costs $400, 2Gb of registered ecc corsair ram costs $1100... right there you are already over my budget of 2 grand. Because my application, Ansys, doesn't scale well with multiple processors in the windows environment if I went with cheaper processors and a 333Mhz fsb board I'd be making a computer that is slower than a single processor AMD64.

This leads me back to the point of this thread. Has anyone tried putting 4Gb in their AMD64 socket 939 board?
 
Met-AL said:
ROFLMAO!!!!
Does the memory haved to be in the matched sets like l337zax said? I thought that was just marketing BS.
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Shouldn't have to be matched sets, however, probably would be to the benefit of system stability if they are. Each one of those 2 gig sets of ram he is looking at are more than likely matched sets.
 
I have worked with 4gb of ram a lot its not entirely posible. Your OS will only see any where between 3.1 -3.45 gigs of ram. To see all 4gb you will need PAE which may make your system very unstable.
 
This is true. AMD's architecture reserves a portion of 4GB of RAM for ... stuff. Not really sure what, but I guess Intel's is the same way, assuming it's all straight-up x86 across the board (pardon the pun).
 
I don't see exactly why you'd need 4 gigs o' ram. Even if you're doing mathematical computation, 2 gigs would probably be more than enough. I really wouldn't use 4 gigs of ram unless I got into the server side and was running dual opterons.

If you're worried that much about math computation and memory resources, I'd honestly make the jump into a dual processor system, preferably opteron. They'll blow your single socket A64 3500+ out of the water as far as computational speeds go.
 
jack_r said:
I've looked at the dual opteron option and deemed it infeasible with my budget. For instance, 2 opteron 244's cost $600, a dual tyan 400mhz fsb board costs $400, 2Gb of registered ecc corsair ram costs $1100... right there you are already over my budget of 2 grand. Because my application, Ansys, doesn't scale well with multiple processors in the windows environment if I went with cheaper processors and a 333Mhz fsb board I'd be making a computer that is slower than a single processor AMD64.

This leads me back to the point of this thread. Has anyone tried putting 4Gb in their AMD64 socket 939 board?
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so try the slower opties if they are too much. If Ansys isn't multi threaded, well that just plain sucks :p
 
Hey All,

Well, I've been lurking here and listening to you all:) Thanks for the info. The last of the parts for my new computer arrived yesterday. Here's the specs...

AMD 64 3500+ (Socket 939)
MSI K8N Neo2 Platinum Motherboard
4 GB Corsair XMS Ram (4x1Gb sticks)
Raid 0 pair of 36 Gb WD Raptor (10k RPM) Sata Drives
80 GB Seagate 7200 RPM IDE (for storage)
Antec Worstation Case with True 550W PSU
Radeon 9600 Pro AGP card
5 Panaflo Fans (Japan made)
Samsung CD-RW 52X, DVD ROM 8MB cache
Samsung CD-ROM 52X
Zip Disk, Floppy, round cables, HD Cooler, etc..

Haven't yet had time to run comparative benchmarks or optimize the system much. I have been able to get the ram running at 3-4-4-8 (2T)
with a FSB of 200Mhz. I installed Win XP 64 Bit edition (latest beta) first and was amazed at how much like Windows XP 32 Bit it is, and also how polished it is for a beta 6 months to a year before production. It recognized 3.25 Gb of RAM as does my motherboard bios. I haven't been able to figure out how to tweak things in the bios to recognise more ram (any imput would be helpful here.) Unfortunately there were several issues... I couldn't make Windows update run, couldn't install macromedia flash, and ANSYS (my main FEA program) kept crashing. SO.... I wiped the drives and installed Windows XP 32 Bit... surprisingly I hit CTRL-ALT-DELETE and the system recognised 3.25 GB of ram right away... I thought Win XP 32 Bit could only recogznise 2 GB of ram???

My first impression is how amazingly fast the SATA Raptor Drives are... unbelievable... I installed Windows XP in under 10 minutes (it was totally fun watching the "time remaining for install" counter count down a minute every 10 seconds.) Also, its amazing how well this machine does multitasking... keep in mind that FEA programs are a beast... I have regular access to numerous Pentium 4 3.0 Ghz (1GB ram)based computers and when Ansys is solving you'd be lucky to get Internet explorer to open in 30 seconds. This AMD machine lets me browse the internet, and design parts in Solid Works with no noticable loss in performance while ANSYS was solving... unbelievable!!! I realized that ANSYS was being slowed down... my point is just how well multitasking is implemented on this machine.

I have much to learn about ram management... this is my first computer with crazy amounts of ram. It seems (from the CTRL-ALT-DELETE performance tab) that ANSYS isn't making good use of the ram... and the hard drives are still being used during the solve (though infrequently). As a first impression though, another graduate student and I raced my computer and his older Pentium 4 2Ghz (512MB ram) system against mine running the same FEA simulation... and at one point after an hour or so we noticed that my machine was at 125 iterations of a solution while his machine was still at 12 iterations... wow:)

Hope to have more to report soon...
 
l337zax said:
I don't see exactly why you'd need 4 gigs o' ram. Even if you're doing mathematical computation, 2 gigs would probably be more than enough. I really wouldn't use 4 gigs of ram unless I got into the server side and was running dual opterons.

If you're worried that much about math computation and memory resources, I'd honestly make the jump into a dual processor system, preferably opteron. They'll blow your single socket A64 3500+ out of the water as far as computational speeds go.
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I run 2 Gig, and in the following Matlab script, anything over about a 900 by 900 mesh kills my machine (X1Steps and X2Steps in the script) - out of memory errors. This is a short thing I did for an Optimization course I am taking in graduate school- Civil Engineering / Structures.

Code: 
% CVEN689.600 - Optimization
% Homework #2
% Problem 1

clear;
clc;

i = 1;
j = 1;
X1Steps = 900;
X2Steps = 900;

X1Min = -10;
X1Max = 10;
X2Min = -10;
X2Max = 10;

X1Increment = (X1Max - X1Min)/X1Steps;
X2Increment = (X2Max - X2Min)/X2Steps;

zValues = zeros(X1Steps,X2Steps);

for i = 1:1:X1Steps
    X1i = i * X1Increment + X1Min;
    for j = 1:1:X2Steps        
        X2i = j * X2Increment + X2Min;
        
        zValues(i,j) = 0.5 - ((sin((X1i^2+X2i^2)^0.5)*sin((X1i^2+X2i^2)^0.5))-0.5)/((1+0.001*(X1i^2+X2i^2))^2);
        
    end
end

% Plot 3D Surface Mesh from workspace

Here's what you get out of that jumbled mess above: Really hard to see the function's optimal value.

Resulting plots (2) with 50 x 50 mesh:

OPT_01.jpg

OPT_02.jpg


High Resolution, 900 x 900 mesh:
OPT_03.jpg

OPT_04.jpg


You are easily able to see the global optimum in a high resolution graph- It's lost in the 50x50..

Memory Space and Performance are critical in some areas.. MATLAB can eat your lunch very quickly.

Processing Power is not the issue all of the time; as you can see with this script the only issue is available memory- the calculation is not very intensive. The script runs in about 3 seconds at 2000x2000, but it's a nightmare to graph, due to the memory requirements.
 
jack_r said:
...
ANSYS (my main FEA program) kept crashing. SO.....
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So, how again do you have ANSYS on your private machine?

I've actually written my own FEA code- but ANSYS has such a neat user interface... it's amazing what you get for 5 figures (Annual software fee!!) these days...

Also, from my P4-1.8Ghz and P4-3.2Ghz I noticed a 5 fold improvement in performance between the two. Most notably is the SETI@home performance- the new one can do 6! unitss before my old come completes one.
 
This guy i know has 4 gigs in his machine, but I don't think it's really worth it...at that point I think the extra memory is a disadvantage in regards to price vs. performance.
 
jack_r said:
I wiped the drives and installed Windows XP 32 Bit... surprisingly I hit CTRL-ALT-DELETE and the system recognised 3.25 GB of ram right away... I thought Win XP 32 Bit could only recogznise 2 GB of ram???
Click to expand...

32-bit systems can address up to 4GB of RAM, though as noted above some of it gets reserved for device addresses (like PCI and AGP).

2^32 = 4,294,967,296
 
reply to #29

This is my school "research" machine... we have a site liscence to Ansys... its legal...
 
jack_r said:
reply to #29

This is my school "research" machine... we have a site liscence to Ansys... its legal...
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Sweet- have fun! :D (If that's what you call it)
 
Another option for 4GB is Xeons or Athlon MPs. Most of the MP boards can handle 4GB of installed memory, and some of the dual Xeon boards can handle 8GB+ Of course that requires horribly expensive 2GB Reg'd ECC DIMMs. An added bonus w/ the new 64-bit Xeons is unlike Opterons you don't *need* 2 CPUs to fill up the ram banks.

As for the problem w/ not seeing 4GB, you're probably getting hosed by 32-bit PCI/AGP. It's only a 32-bit address bus, so some of the memory space gets sucked up by memory mapped IO devices. Kinda like the old days where if you put an ISA vid card in a machine w/ >16MB of ram you'd wind up w/ a "hole" in your memory. I'm not sure what you can do about it. Just out of curiosity, have you tried Linux on the machine?

I'll be joining the 2GB club later this week. I just ordered a 1GB Reg'd ECC PC2700 module for my duallie Athlon XP (modded :). You'll all think I'm nuts, but I'm writing a search engine for a 2 million item product database, and I'll need the extra ram to keep the entire index in memory. My preliminary calculations put me at around 1.5GB, so hopefully 2GB is enough. If not, there's one more slot free...
The search engine might run OK if it swaps a bit, but the indexing process will kill me if I have to dig into swap space.
 
jack_r said:
I've got an Antec True Power 550W on order;-)
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NO NO NO! You need a GOOD power supply.

Please get an Enermax, Sparkle, or PC Power and Cooling..


the antec 550 is a CRAPPY psu.
 
I disagree about the antec psu. It recieves good reviews from many hardware review sites on the web. While it might not be entirely gold plated, nasa engineered, and hand polished by little electron fairys, its certainly a good choice, and at $105, not a bad deal either.
 
jack_r said:
I disagree about the antec psu. It recieves good reviews from many hardware review sites on the web. While it might not be entirely gold plated, nasa engineered, and hand polished by little electron fairys, its certainly a good choice, and at $105, not a bad deal either.
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Before Making a Thread About Buying a PSU...

High End = $100-$199

I do feel obligated to say that although I listed the Fortron 530 and Sparkle 530w PSU's (same ones) in the last category, I did that soley because of price. They will outperform almost every psu in this category despite their mid $70 price tag.
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