RAM where does it go??????????

[bigpig]

I"m using the rambooster program to track my ram, I had 96megs, and when surfin the net I would have on average 25megs free. I just added another 64megs for a 160 total and now I average 55 free megs. I figured I should have about 90 free.
Does this make any sense?

[stu]

Well I run 256 megs and sit on about 175 free. I know windows takes some up and whatever you have running in the background will suck some in but this question continues to puzzle us

[BEOR999]

This is one of the most misunderstood aspects of the memory caching equation. The amount of RAM that the system can cache is very important if you are going to be using a lot of system memory. Almost all modern fifth generation systems can cache 64 MB of system memory. However, many systems, even newer ones, cannot cache more than 64 MB of memory. Intel's popular 430FX ("Triton I"), 430VX (one of the "Triton II"s, also called "Triton III") and 430TX chipsets, do not cache more than 64 MB of main memory. There are millions and millions of these PCs on the market.

If you put more memory in a system than can be cached, the result is a performance decrease. The speed differential between the cache and memory is significant; that's why we use it. http://www.sysopt.com/forum/smile.gif When some of that memory is not cached, the system must go to memory for every access to that uncached memory, which is much slower. In addition, when using a multitasking operating system (pretty much anything other than DOS these days) you can't really control what ends up in cached memory and what ends up in non-cached memory, unless you really know what you are doing.

I would therefore guess that Win9x is caching all available memory above 64mb.

[J]

Uhh you lost me so what is cache anyway and what does it have to do with system memory and avalable memory and speed?????????

[BEOR999]

well, first off do not confuse cacheable memory with L1 or L2 cache memory, thats the 512k cache, that you see listed on the spec for the PC.

The OS will cache as much memory as it can, 128 MB of maximum, correct me if I'm wrong http://www.sysopt.com/forum/smile.gif and will look at it before it look's in the win swapfile, or virtual memory to you and me. This Cached memory, like all type's of cache memory acts as a buffer for recently-used information to improve performance.

You sorta have to get it into your mind that there are several different 'layers' of cache memory.
What happens in general terms is, The processor requests a piece of information. The first place it looks is in the level 1 cache.
If the required info is not there then level 2 cache is searched. If it finds it there it is able to continue.
If not, it must issue a request to read it from the system RAM.
And if it still cannot find the info, then it (the cpu) will have to look in any/all available devices connected to the system.
This long process will obviously affect the speed at which you percieve the system is running. So the more memory that can be 'cached' for the storage of date, the faster it all is http://www.sysopt.com/forum/smile.gif

Does that make sence, I hope so .....

[J]

no it doesent makesence why does it do it that way I thought that when the cpu wanted some more data it looked in a content table in memory to see where it was and then it goes and gets it. I thought cache was a place for the cpu to store stuff in between calculations that it will need imeadiatly.

thats what I thought happened, now I am confused.

[This message has been edited by J (edited 12-20-1999).]

[BEOR999]

>I thought that when the cpu wanted some more data it looked in a content table in memory to see where it was and then it goes and gets it.<

Well it does, whether or not there is a 'content table' or not, I don't know. But it will not look in system memory first, as that is slow, compared with the speed of the cpu, so it looks in L1 cache, themn L2 then cached sys mem etc.....

The cache (any type) stores most accessed, and recently accessed data, so you do have the correct understanding, in fact you probablly have better knowledge than most people do.

As to why it does it that way, aside from being the fastest way, I guess that's a question for some 'boffin' and not me, I just know that's the way it is http://www.sysopt.com/forum/smile.gif

[J]

Oh...


The reson I wanted to know is because my motherboard cache is bad and I have it turned off in the bios. I wanted to know what that does to my system in performace decreace. Kinda looks like i outa get a new motherboard.


If I get a new motherboard what shall i do with the old one? Oh I know give it to my perents (mischivious grin)all I need is a cheep socket 7 cpu! (can I realy get a AMD K6-2 400 for $50?)

[This message has been edited by J (edited 12-20-1999).]

[BEOR999]

That could cause as much as a 25% de-crease in sys performance http://www.sysopt.com/forum/frown.gif
Time to spend that hard earned cash I guess

[J]

oops...

[BBA]

bigpig,

The amount of ram you have vs the amount free is not proportional. Windows automatically uses a ratio of ram for file caching and changes this on the fly. However, you can manually set the amount of filecache for better performance. You will notice it because it will stop some of the unneccessary disk activity Windows does in resizing the file cache.

It can be set by typing in two lines into SYSTEM.INI under the [VCACHE] header, IE:

[vcache]
MinFileCache=50000
MaxFileCache=50000

This allows me to use about 1/4 of my 192M of ram as file cache. 1/4 the amount present is what you should shoot for, but with less than 64M, You won't notice a difference.


BEOR999

Intel's popular 430FX ("Triton I"), 430VX (one of the "Triton II"s, also called "Triton III") and 430TX chipsets, do not cache more than 64 MB of main memory

That is not really correct. The only Pentium series Intel chipset limited 64M was the 430TX, the older ones could cache a much higher amount (about 512M I believe), and the early P2's were limited to caching 512M ram, but all after that can cache 4G of ram, but the motherboard designs could only use around 768M, unless it was a dual CPU board, which could cache around 1G (including the FX chipset)


BBA

[OuTpaTienT]

Thanks BBA, I was pretty sure that the 64mb limit was experienced by only one type of Pentium board (tx), but BEOR999 was so "right-on" about so much other stuff, he had me questioning myself.

I have 192mb and wouldn't mind having 256 (or a few Gb for that matter).

[bigpig]

Thanx for the replys. Food for thought!!

[EVGTech]

right windows will use quite a lot of memory for file cacheing. In fact the more you use the system the more it will. I dont know that there is a limit to the amount of memory it will use for file cacheing unless you force it.
Win98 windows is pretty smart about this. It will execute a program from the cache memory so limiting the cache size in win98 is not real usefull. Win95 isnt so smart and will actually copy the memory out of the file cache into user memory. nutty.

For main boards lack of cache can make a huge difference in performance. In some cases much more then 25% especially if you have a fast CPU and are running memory hungry programs.

[Gum]

Simple, juz listen to BBA!!

It's the Windows DiskCache that's eating up all the RAM you installed in your system. Windows will allocate as much physical RAM as possible for it's DiskCache.

My 128Mb machine is left with about 70Mb free RAM after booting up and not running apps except SysTray apps namely Noton AntiVirus, ICQ99b, Adaptec DirectCD, Matrox PowerDesk, and WaterFall v1.23.

MaxFileCache=10240
MinFileCache=10240
ChunkSize=512

Hope this helps!! :-D

[EVGTech]

Like i said win98 is supposed to be able to execute a program directly from cache so limiting cache size for win98 is not terribly usefull.

Win95 can have two copies of the program in memory. one in cache and ine in user memory. But i have never found much of a real speed benfit from forcing cache size.

[BBA]

Hi EV...

It's not really the execution of applications from cached ram that provides any noticeable improvement, it's the fact that windows does not have to resize the filecache when it is static (hard set).

This, along with hard setting the pagefile/swapfile and killing the MS Office FastFind feature yeilds an extremely more pleasant computing experience, because you will never be inturrupted by seemingly spontaneous hard drive activity that slows your game or avi file to a less than a few frames per second, or that stops your curser from typing when you are in the middle of a big document or such...

[EVGTech]

I would agree with that if you have plenty of ram but keep in mind that windows will cache a huge amount of info from the hard drive. Just loading windows 95 can take 32megs of cache. I would be interested in hearing your experience with file cache settings for win98.
As i understand it if a program is executed from the cache then it really doesnt matter if the cache is resized as the program would be loaded into memory anyway. There might be some overhead in the file cache resizing but is it really that telling.

it may be usefull to figure how much memory windows devotes to filecaching on a use by use basis. I have a feeling that optimum filecache settings will very greatly from person to person.