Thinkpads Forum

Not sure if this is the right place to ask but I just added 4GB RAM to my x200 (wahoo it's fast!). Previously I had 2GB.

When I had 2GB, the static level of usage was ~1.1GB (nothing open). However now when I have 4GB, the static level is ~2.1GB.

This question is NOT about the "free" memory, I know Vista uses extra RAM space to cache and the free memory is always nearly 0.

Why is there the increase?

mooingmooseman wrote:I know Vista uses extra RAM space to cache and the free memory is always nearly 0.

Unless you are quite tightly constrained in terms of overall memeory, that's certainly not the case.

The X61 ThinkPad, running Vista x64, that I'm typing this message on has 4GB of memory installed and is currently showing 1557MB out of 4GB in use (~38%)... running several open applications and browser instances!

Cheers,

Bill B.

bill bolton wrote:Unless you are quite tightly constrained in terms of overall memeory, that's certainly not the case.

The X61 ThinkPad, running Vista x64, that I'm typing this message on has 4GB of memory installed and is currently showing 1557MB out of 4GB in use (~38%)... running several open applications and browser instances!

Bill, I believe the OP is referring to the free memory under total and cached memory in the Windows Task Manager, not to the green bar.

Marin

Yes Martin, you are correct. I referring to the number next to free memory. I just wanted to point out that's not what I'm talking about.

Does anyone know why memory usage doubled at a static state when I install double the RAM? FYI I'm also running a 64bit Vista so I recognize all 4GB

It's because vistas memory management is smart and prefetches more things.

As long as you arent paging to disk, there should be nothing to worry about, even if it's reporting 95% ram usage. vista will evacuate in an instant the ram needed by whatever program is active and up front.

Is this really anything new? I remember more than 10 years ago I used WIN NT with 128MB RAM and it used ~60 something MB right after boot up. A friend had only 64MB install and for him, it only used 35MB or so (I don't remember the exact numbers as it is that long ago, but the figures are in that ballpark).

Still, 2 GB just after bootup is quite a lot... I´m also interested in hearing something more about it. It´s a fact that Vista has very different memory management than XP, it is more efficient (but not always more effective when needed to start a new application due to memory reallocation flaws in Vista memory management...) and tries to utilize the available memory (unlike XP, which tries to stay in the down levels all the time). I believe the integrated graphics may have also added something to it since it shares from the system memory.

Marin

EDIT: And btw I think staying at 0 free memory all the time is a little nightmare...

basketb hit it on the nose. i don't not believe this is a vista problem-- it's always been like this. i'm just asking why, that's all. my computer's still faster with 4gb, i just want to understand the logic behind it.

for everyone commenting about vista's superfetch and cache, this is not the question at hand. i know vista caches. the increased number does not represent the cache. the cache is reflected in the nearly 0 "free memory".

I believe the memory arithmetic is not very simple, but I don´t know how it works. Right now I have commit memory (the green bar) at 1.3 GB, total 3069 MB (due to hardware limitation), cached 2040 MB and free 3 MB My ATI card can utilize up to 1565 MB memory (256 MB dedicated + Hypermemory) depending on the work load. To make things a little bit more complicated, a loot at Process Explorer from sysinternals tells me Commit 1.6 GB, total 3143 MB, available 1739 MB, system cache 295 MB. I don´t even mention the kernel memory I´ve been looking for clear explanation of this "arithmetic" for weeks. However, I can one for sure tell that commit and cached are not independent (for the simple fact that their total sum is more than my available RAM, hence some part of them follows to be shared by both indicators -> go figure...).

Marin

EDIT: sorry, this doesn´t really seem to be an explanation to your question

Marin85 wrote:I believe the OP is referring to the free memory under total and cached memory in the Windows Task Manager, not to the green bar.

The Task Manager Performance tab Physical Memory numbers on the T400 I'm typing this message are....

Total 3991
Cached 1567
Free 1030

Free Memory is still a long way from 0

Cheers,

Bill B.

Bill, I think the free memory depends very much on what you do. Immediately after boot, there is still plenty of it, but after "doing" some word, excel and Firefox, this indicator easily drops to 0. I think the point with the free memory is just that it easily drops to very small numbers without any apparent heavy usage. For all programs that aren´t in the cache in this very moment this situation makes Vista open them much slower even though the physical memory usage doesn´t even reach its maximum. That´s one of the reasons why I´d like to understand how this whole "memory arithmetic" works.

i remember i was able to increase free memory in vista by disabeling some background aplications and services. i think superfetch might also have to do something with it. my windows 7 gives me 2300 free memory with taskmanager, and 2 internet explorers open.

Bill/All,

I want to clarify a few things:

1. We’re talking about Vista OS
2. My stats this very moment are
Physical memory usage = 2.04GB
Total = 3991MB
Cached = 2280MB
Free = 6MB
3. The 2GB I am quoting is “Physical Memory Usage” in the Task Manager
4. Vista uses excess memory as cache (superfetch)… that is why my TOTAL – PHYSICAL = CACHED + FREE
5. Question is why Physical memory usage doubled when my total doubled (by installing more RAM)

Seems like no one really knows but that I’m not the only one to observe this issue.

@mooingmooseman: I´m not sure what kind of answer you are looking for. There have been already a few suggestions (maybe not very complete though) as to why your X200 shows increased "stock" physical memory usage after upgrading the system memory. Here is what I believe is the reason for the memory observations you have made:
1. Cached is actually not the same as prefetch/superfetch. Even with prefetch/superfetch functionality turned off, Vista OS keeps on caching. I can confirm this as I have prefetch/superfetch disabled from the very beginning on. Vista caches programs/windows components depending on the available RAM once these components/programs have been launched for a first time after windows startup. That´s why loading programs for second, third etc time is so fast, in fact much faster than the initial launching.
2. The idea behind prefetch/superfetch is to observe user´s activity in an intelligent way and to load mostly used components at the end stage of the boot process directly into system memory. Its aim is to deliver faster loading of programs/components even before they have been used for a first time after windows startup (that´s why the fetching occurs right after/during the boot). The amount of prefetched/superfetched data again depends on the available system memory.
3. If prefetch/superfetch is enabled (which is the case with Vista per default), then clearly they become part of the cache.
4. Now, part of the cache is also part of physical memory usage. If you take a close look you will see that cache often exceeds physical memory usage. The difference cached - physical memory usage is so to say what Vista is ready to free up in order to load another program provided the free memory is insufficient for this task. If even that is not sufficient, Vista would free up even more from cache to have space to load the new program.
5. Free + Cached is never equal to total because the other part of physical memory usaga (the part that is not from cache) has to be added to this (these are things that are loaded into the system memory but are not available as cache). System memory locked by the gpu should be considered as well.
6. Why physical memory usage is not completely part of cache - is because not everything is needed as cache and the amount of available RAM is still limited (even with 4 GBs). For the same reason Vista doesn´t try to cache the whole HD.
7. My answer to your question: The reason for the increased stock physical memory usage (that´s what I call the physical memory usage after the system has completely booted up) is prefetch/superfetch, because they share a part with the physical memory usage and load things into memory on boot and positively depends on the available physical memory.

I know, I could have skipped right to point 7, but I believe in this way things become more clear as to why this or that

Hope this answers your question

Marin

sounds like a good explanation, thanks!! makes more sense to me.

Actually, you could try the following experiment if interested: you can reinstall Vista on your machine with only 2 GBs of RAM installed into it, disable superfetch/prefetch via registry from the very beginning on (i.e. before installing any programs), install your programs, observe the "stock" RAM activity, install the other RAM module and compare... and not forget to post back

Cheers

Marin

hi guys, abit off topic, but my x200s only came with 1gb of ram, i'm thinking about upgrading , it is better to grab another 1 gb of ram so it runs in dual channel or does that not apply to laptops and just grab another 2gb instead?


thanks.

The dual channel question has been covered many times in this forum, including in recent threads -> forum search can be a good friend

Put simply:
1. If both memory slots are occupied, then the memory operates in dual channel mode.
2. If both memory sticks have the same size, then they operate in symmetric dual channel mode.
3. If the memory sticks have different sizes, then they operate in asymmetric dual channel mode.
4. Performance-wise: in memory-intensive tasks the asymmetric dual-channel couldprovide up to 8% performance boost over non-dual channel mode, whereas symmetric dual channel mode can provide up to 10% performance boost (in the same situation) over non-dual channel mode. Hence the performance difference between symmetric and asymmetric dual channel mode is marginal.

Hope this helps

Marin