Hard drive space used as RAM??

[adinu]

One of my friends showed me an option where you can designate a certain amount of HD space to be used at RAM.

In the beginning, I had 512mb of ddr pc3200 ram and like 700mb of hard drive space used as ram. In the task manager,when I was around like 500mb of ram used, it was like almost half way up the little scale that they have.

He upped the HD space to 2500 mb, and now when I look in the Task manager, if I have 500mb used by processes, it barely goes up 1/5th of the way up the scale.

Can somebody explain what this means exactly, or how this works, because it seems taht I just have more ram to work with, but that cant be...

 

[uzi9mm]

Your computer uses your HD as "virtual memory". You HD is like a big stick of RAM , but it is really really slow compared to a real stick. You can allocate different amounts of Virtual mem or page file space. If you have at least 2 gigs, sometimes its recommended to turn the page file completely off for better performance.

 

[Elbatrop1]

Ya, what he said^^^^^

Also, it is recommended to make your virtual memory 1.5X the amount of RAM you have.

 

[adinu]

So what happens if I set the virtual memory to more than 1.5x the actual RAM? Are there any actual performance improvements or is the 1.5x pretty much the limit, after that just a waste?

 

[Elbatrop1]

If you go too much over that, Windows will think it has a whole ton of RAM, and use the virtual memory a whole bunch. When this happens, you'll likely significantly shorten the life of the hard drive, becuase its being used so much.

 

[TheMajor]

I don't think it makes sense to set the pagefile at 1.5x the amount of RAM. You have more RAM, so you need less pagefile. I even think it gets faster if its smaller. Just make sure its large enough. Open 20 programs and see how much you need.

My 2 cents.

 

[Elbatrop1]

Good point Major. The 1.5X is Microsoft recommended, but we all know that they have been wrong once or twice before.....

 

[Chankama]

The "virtual memory" - which tends to be larger than the actual "physical memory" (RAM) on a given computer - saves the programmer of an application from worrying about these memory issues. They can allocate memory to their hearts content and just let the operating system worry about memory management. If you have this massive memory chugging application, and you have like 10 GB of virtual memory (which someone I know is doing on a database server they are running), the operating system will bring information to the RAM (actual memory) on a needed basis. The programmer can say, "well give me the information located in memory address 0xABC...DEF". The operating system will check if this valid virtual memory address is in the RAM, and if not will go to the hard drive and bring it to the RAM and then give this to the application.

Really, you can have as much virtual memory as you need if your application wants it - for ease of programming. If you have a huge database server running as I said, and you want to have all of it in "memory" for whatever reason (without having the programmer worry about how much memory will be on the deploying hardware), you can just allocate insane amounts of "virtual memory" and let the OS worry about appropriate swapping from HD to physical RAM.

 

[TheMajor]

My swap is set to 600MB, I only have 256MB RAM. 1.5x wouldn't be enough for me, but it wouldn't make sense to put your swap at 15GB if you have 10GB of RAM.

 

[AT2005]

I wouldnt mess with that too much because you might trully F suomthing up. Im a comp tech with and ITT tech certification, but Im working hard to get My CISCO done and start by MCSE, Anyways I had one client that would call me almost 4 times a week to fix his Virtual mem screw ups. I wasnt upset at the guy being stupid I liked to go because he was paying me 20 bucks an hour which is kinda crappy but it does well. IF you still want to try it read some info on it and find out a multiplier