What determines the maximum RAM memory?

hi folks!

a simple question: the maximum memory which is installable in a computer, is determined by what? the chipset i suppose, right?

So if the chipset manufacturer website (we are talking about an Intel PM45 with 82801IBM I/O Controller) states that can take up to 8 GB memory
meanwhile the laptop manufacturer website and various other websites (Samsung Q320) state that the maximum is 4 GB
question is, which source should i trust more?

I would say the Intel source, do you agree?

 

They are both correct.

In this case, Laptop manufacturers just limit the maximum RAM through the BIOS. Its silly but some of them still do it. Check your latest BIOS update log to see if they unlock it.

Laptop manufacturers are also known to disable IVT (Intel Virtualization Technology) even though the CPU totally supports it.

 

You also may wish to check the dates of some of those publications. The laptop manufacturer and other websites may date from before the introduction of 4 GB SODIMMs, which would mean that when they were published, 4 GB was the maximum. Oftentimes these publications are not updated as time goes on. And yes, it's not unknown for manufacturers to limit the capabilities of their machines, either through BIOS or other hardware/software locks.

 

this ain't good news!

actually the laptop is quite recent and I think 4 GBs SODIMMs were already on the market.
SIW also report 4 GB as the total maximum supported.
Indeed I just found a table from the manufacturer that state all the possible RAM upgrades and (just few actually) laptops are listed as 4GB default, max 8, meanwhile mine is 4/4.
Sad.
I'm diggin to search for BIOS updates, but i'm afraid my lappy is not anymore supported.

If the manufacture was so irritant to block the chipset, what would you think will happen if I mount a single 4GB stick?
fully recognized, just 2GB recognized (as I have 2 slots, so if the max accepted is 4, maybe each slot has a max of 2) or just error?

thank you!

 

My Dell E1705 was listed as supporting a maximum of 2GB, even many 'memory upgrade' advisors listed it as so. Intel on the other hand said the chipset supported 4GB and as this was a 2006 system, I was sure it would support 4GB without problems - tried it (2x2GB sticks) and didn't have any problem detecting or running with 4GB.

I would say if the chipset/CPU/etc combo is known to support it then give it a shot, bet it will work regardless of what the manufacture is telling you.

edit: your sig says you have 32-bit Windows, you *will* need to upgrade to 64-bit Windows/OS to be able to detect and properly utilize it. If your system was sold with only 32-bit Windows, then that could be the reason they say it only supports 4GB. 32-bit Windows max RAM = 4GB, 64-bit (Windows 7 Professional) = 192GB. Advise: Find a 64-bit ISO/CD of Windows 7 Professional and you should be able to use the same 32-bit license key with it without the need to purchase a new Windows license.

Your CPU checks out as 64-bit, chipset (according to Intel) supports upto 8GB - upgrade your OS to 64-bit, install 2x4GB DIMMs and it should work (sparing any strange BIOS limitations, but I doubt there are any). Buy from a store with a good return policy and you're covered in any event.

 

Chipset Limitations - Check the whitepapers on the chipset it should list memory address space. It must be higher than the amount of RAM you want to install.

So older chipset that say 8gb memory address space do not support up to 8gb of RAM because there must be memory address space left over for the system to reserve for itself outside of the usable memory space.

BIOS - Already mentioned but no matter what the hardware supports if the BIOS interface has not been programed in a way to support the same as the hardware it can limit you.

Software O/S - Pretty well known by now but you can not use more than 4GB of ram in a 32bit OS environment. Same reason as before its memory address space. With 4GB of ram you get like around 3.4gb of RAM to use in the OS so to get past that 4GB limit you must be using a 64bit OS. I say software/os because that is a lesser known fact that no single application can use more than 4gb of RAM even in a 64bit OS unless it has a 64bit binary that you are using. So doing video editing or photoshop on a 16gb RAM machine, unless your using a 64bit version of Photoshop or your video editor you can only allocate the 4gb of RAM limit to that program.

 

True but BIOSes aren't created from scratch from the ground up for every system, they use a generic template that supports all the hardware features and has all the basic BIOS features. Unless the manufacture went out of their way to create a limit, it should support all that Intel intended and the hardware was designed to.

BTW - 8GB memory limit means it supports being equipped with 8GB of RAM. OS/BIOS will always reserve amounts of RAM, it has nothing to do with what the chipset/hardware will accept.

 

'Judicator' is accurate in his/her statement that both the chipset manufacturer and BIOS maker claims are correct.

In a lot of the cases though, it's the BIOS that is artificially limited.
Predominantly because it's not in their interest to create a highly modular laptop (or versatile BIOS supporting ALL chipset functions) that would allow people to simply upgrade various components over time and overall spend less money than they would usually on a completely new laptop (although, certain laptop component prices are often high enough that they don't really justify the upgrade compared to simply buying a new laptop).

My laptop has a PM45 chipset. It's designed to take up to 8GB RAM to my knowledge (I think a source or two claimed 16GB, but I cannot be sure of that).
Either way, the problem is that since my laptop also came with 2 RAM slots (which support DDR2 sticks) it's pretty difficult to upgrade because 4GB DDR2 sticks aren't exactly widely available for a cheap price (at least laptop ones aren't).

Now, it's also a question of whether or not my laptop would even recognize and access all 8GB RAM.
Acer never bothered to upload a document which states revisions for the last BIOS version they released (even though I upgraded to it immediately) and their customer service was of 0 help.
Plus no new versions of the BIOS came out ever since then.

Laptop manufacturers stop releasing new drivers and BIOS revisions relatively shortly after a unit has been launched (drivers more or less within the first month or so, and BIOS sometimes last a bit more).

The only way for me to know if my laptop actually can work with 8GB RAM, is to get the 2x4GB DDR2 sticks and test it myself (which isn't really cost-effective for me right now).

Usually, if you want to upgrade the laptop on your own and max out it's potential for minimal cost, you cannot expect support from the manufacturer.

But 'gaah' is also correct for the most part in stating that virtually all computer BIOS-es are based on a generic template, and it does depend if the manufacturers went out of their way to limit support irrespective of the chipset.
Unless the BIOS documentation states it, but the chipset manuf. does, then you are left with testing if something works on your own.

 

No one has mentioned the number of physical slots also factors in the max memory a laptop can accept.

Most laptops have 2 slots which currently would limit the max to 8Gig

However there are some laptops that have 3 or even 4 slots.

The Asus N73 has 3 slots and has a limit of 12Gig, while the G73 has 4 slots limiting it to 16Gigs.

My Sager has 2 slots so its limit is 8Gig.

All the above laptops use the HM55 chipset, which really does not matter as the i series CPU's have the memory controller built on the CPU.

 

Actually, OEMs have 8GB memory sticks (such as with Dell's Precision line).

 

Say what? Of course it will support 8GB of RAM if it says it will. The 'reserved' stuff is taken directly from the 8GB, or whatever amount of RAM is installed.

 

IMO , the max is limited by chipset limitation and RAM slots.. in the 965 intel series , it was more of a chipset limitation.. from the 4,5 series , its the number of RAM slots... an Asus G72GX could go to 12GB on PM45 chipset.. i7s can take 16GB or 32GB...

ya , 32GB of memory costs a few times more than the M6500...

 

The 45 chipset should support more than 12GB. It's more likely to be limited by the BIOS.

 

all ur saying is exactly the same for me
and PM45 is the chipset I'm having, and it is claimed to support up to 8GB ram.
and sadly, as you said, upgrading to 8 GB is a costly operation that can lead to no results.
Buying a 4gb stick is almost 100 euro and it might works alone cos it is just 4gb. then if I buy another stick, and it doesn't work, I've spent 200 euro for having a computer with 4 gb; I could have obtained the same result spending 30 euro and buying another 2gb stick, totaling 4gb.
shame!

___

indeed, stupid me, If I buy the 4gb stick, I can mount it with the 2gb stick I already have and see if the system detect 6 or 4 gb. But still, is 100 bucks, not really tempting

you are completely right, just forgot to update my sig.
anyway your suggestions of buying from a shop with a proper return policy might be the solution - but that exclude cheap shops on ebay shipping from korea

 

I think nobody mentioned it because its sort of a given

 

Chipset/Hardware is a limitation. If your chipset is older and does not have the max address space needed you can never use more than 4gb of ram even if all other criteria are met.

The only way around getting the full amount of usable ram in your OS if its the same as your phisical memory address space is with PAE mode, but no laptops that I know offer PAE and its kinda hit/miss in how it works since it consumes the system memory address space it can cause issues with some programs.

I used 8gb as the example but should have used 4gb since that was the common issue, many older chipsets only had 4gb of memory address space avaible, so when people installed 4gb of ram, and installed a 64bit os, they wanted to know why they still could not see & use the 4gb of ram in the OS. and the answer was a chipset limitation.

 

200 euro for 8GB? Naa. I bought from a US supplier it cost me 100 pounds total about 2 weeks back! 8GB of ram is pretty cheap right now. I was waiting for over a year for those prices to get down to 100.

 

The older intel 965 chipsets actually supported up to 8gb but nearly all manufacturers limited it to 4gb.

I remember the dell m1330 A13 BIOS and earlier only supported 4gb then the A14 supported 8gb and the very latest A15 only supported 6gb. That was retarded.

 

Where did you get cheap RAM from?

 

askin the same; please share a link in a private message!

 

Here we go the ebay seller Koybe: 8GB ddr2 sodimm items - Get great deals on Computing, 4gb ddr2 sodimm items on eBay UK!

At least 4 kits like the one I bought for sale there now at 108 pounds. After a bit of haggling which I always do he was happy to part with it for 100 pounds. You are paying in euros which should still make it fairly cheap.

This supplier is great. Good communication and I bought from them before when I got my 4 GB kit over a year back. The ram works very well. Even though it is PC5300 667mhz ram I can easily take it to 730mhz which is my chipset limitation at the timings shown in my sig. Great if you have a locked FSB:ram ratio of 1:1. Better performance than the more expensive pc6400 800mhz ram.

 

well, my chipset is the PM45 and its FSB is 667MHz / 800MHz / 1066MHz..
so what???
shall i take into account the FSB of the CPU then, in order to determine the best frequency for the RAM?!

cos right now my CPU is 667 MHz I think, so it doesnt make much sense that my actual RAM is 800; but later on I would like to upgrade to a CPU with 1066FSB, so it might be worth to buy 1066 MH RAM? (wondering whether they exist at all)

EDIT: yeah, DDR2 range up to 800 MHz..

 

Memory speed has no effect on system performance if you don't game on integrated graphics, so just get the cheapest memory with lifetime warranty. Also, there is no DDR2-1067, nor would the chipset support it.

 

It's not so much the chipset but the memory controller hub usually found in what we classify as a chipset. Up until recently this was always located in the north-bridge chipset. These days more and more CPU models (including those in laptops) have the memory controller within the actual CPU die. The nothbridge chipset is still there except now it's usually called IOH for Input Out Hub. These days it predominantly controls things such as the PCIe bus etc.

So as for what controls the maximum amount of RAM you can upgrade to, memory controller is one but also memory slots is another. The current maximum SODIMM capacity is 4GB. So, take for example a Precision M6500 or W701 laptop, currently the creme of the crop workstation wise. Even they supported 16GB RAM but only had two SODIMM slots, then practically the limit would be 8GB. In such case it's because they equally have a memory controller supporting 16GB RAM and four SODIMM slots that they can be upgraded to the full 16GB.




Upgrading the amount of installed laptop memory - identifying limiting factors

 

Actually, they have 8GB SODIMMs for OEMs. You can configure the M6500 with 32GB of memory.

 

Geez, must have only just showed up. Over $9000 for 32GB DDR3 in a laptop, about the only folks who could use that much work at Pixar, and even then even if they have so much RAM, they'll still be slowed down by the FX3800M graphics.

 

No, not just them, although the M6500 is probably also scheduled to get the FX5000M. Don't forget people who make their living off panorama photography (thanks tilleroftheearth), and those who run multiple VMs for server testing.

 

This is the second time you have posted this information, but I go onto dells website and cannot get the custom configurations to allow me that much ram. Right now I get a limit of 12Gig at an additional cost of $631.

I was curious more than anything to see how much 32Gig would cost. While 32Gig may be available, the cost would be so ridiculous for even a high end laptop workstation.

 

You need to go the the "Large Enterprise" section to configure one. Upgrading to 32 GB of RAM is listed as a $9,194 upgrade ( The Dell Online Store: Build Your System).

 

Yea, I see that now, all I can say is "Holy Crap"

My configuration came out to $14,500. I think the WAF factor is approximately zero on that.

So while there are machines that can take 32Gigs of ram, in all practical purposes 4 Gig or 8 Gig is really the most cost effective, and really what most people will ever need.

 

Oh, certainly. Those that actually need that much RAM know it already, and it is probably accounted for with their business. I think tilleroftheearth said that if he was doing panorama photography seriously, which would need that much RAM, it would pay for itself after about a month or so of steady work. Not knowing much about the photography industry, I take his word that he knows what he's talking about.

 

nice piece of information, but actually is valid just for really new CPUs; in my case, the memory controller is still located in the northbridge!

so according to your thoughts, your advice is to go even for RAM rated at 533MHz, even if my future CPU is gonna be e.g. 800 MHz??

 

With DDR and dual channel, the CPU still ends up being the bottleneck.

If you were gonna buy new sticks though, 800mhz will probably be cheaper and easier to get a hold of.

 

I'll stated it again... get the cheapest memory with lifetime warranty. Don't worry about the future.