ahallflyertalk

Based on what? Did you find yourself constantly running out of RAM when you had only 2GB, to the point where you noticed your computer slowed down because it was swapping all the time? What's the largest amount of RAM you've ever seen your computer use at one time?

DeafFlyer

I'm using Vista HP 32 bit on a laptop with 2 GB. Comparing that to another laptop with XP and 1 GB, I would say 2 GB for it regardless of OS that you choose.

Loren Pechtel

No. XP can't even use the 4gb, period. If two programs on this box both try to take 2gb, 1gb will end up in the swapfile. The extra memory simply can't be addressed by any means under a 32-bit OS, it's *GONE*.

Loren Pechtel

What you are missing is that that extra RAM isn't sitting idle. Memory not being used for anything gets data that you read from the disk--thus next time you read it it's already in memory. It can make *QUITE* a bit of difference in speed.

Loren Pechtel

It depends on your board & video. My old box got 3.25gb.

Agreed. I would never put 3gb for this reason. Always fill out to whatever the memory pairing is of your board even if it's not required. These days that's 2 chips but there have been times in the past it was 4 and who knows what the future will bring?

ahallflyertalk

Uh, sorry, this is just not true. If you have 2GB of RAM and are using only 1GB, the other 1GB is indeed sitting there idle.

You seem to be thinking of disk caching, which means that the first time you access a file on disk, it is loaded into a cache in RAM (most recently access parts of it, anyway) and any subsequent accesses to the same piece of the file get read quickly from the cache and not from the disk again. But, hard disks themselves have a cache built-in. Computer operating systems may do some disk caching but must reserve RAM for that, and the amount reserved is pretty limited. A hard disk will have a cache of only 8MB or 16MB at most. Not much RAM on your computer's hard disk is reserved for a cache.

ahallflyertalk

In addition, you should note that the more RAM you have, the more hard disk space is required to hibernate. If you have 3GB of RAM, then you need 3GB of free hard disk space to hibernate your computer. If your hard disk is near full, that could make a big difference. Even if you have plenty of hard drive space, the entire 3GB must be saved off to disk (automatically) when you are hibernating and then read back when you resume, so it can take longer. If you have no need for 3GB of RAM, you are still paying a small penalty by waiting a little longer to hibernate and resume, maybe only a few extra seconds but to some, that can be kind of annoying.

kanebear

Absolutely, positively, untrue. Windows adjusts the System Cache based upon how much RAM you have. More RAM? More cache. It does make a speed difference. In the control panel, if you change the setting for optimization of System RAM from Programs to System Cache it will handle this.

CessnaJock

!Bill Gates

More RAM = more heat = more battery drain = less time. In a laptop, this matters. Get 2gb and see if any of your apps get anywhere near using it. Increase memory p.r.n.

ahallflyertalk

Nope. Windows desktop users by default get a program cache of only about 10MB. If you set the performance option under "Memory Usage" to "System cache" it would indeed use up available RAM but Microsoft doesn't recommend that for desktop/laptop computers, only servers. Performance is better with the "programs" option.

For reference, see here:

http://www.techspot.com/tweaks/memory-winxp/

Your hard disk has its own built-in cache of perhaps 8MB or 16MB tops which helps speed performance of disk reads of the same files; there's no need for Windows to duplicate a disk cache, only a cache for applications within Windows.

So once again, Windows (unless you run a server, most people don't) doesn't use up all your unused RAM as cache; that's just not true. It really does just sit there idle.

People who have 2GB of RAM now and aren't coming close to using it all won't see a bit of performance improvement if they could up the RAM to 3GB or 4GB. If you have a need for more RAM because you are running photoshop or other memory-intensive software, or are running a lot of programs at the same time, get the extra RAM, otherwise you are wasting your money.

jerry a. laska

32-bit Windows (XP, Vista) can see up to 4GBs of RAM. But a percentage of that RAM is reserved for physical memory addresses for BIOS, video cards, hubs, bridges, and other, the exact amount is determined by your specific setup, the number of installed devices you have, etc. That's why people are able to report they can see 3.5, 3.25, 3.12, and other amounts.

(I'm not advocating for people to go out and put 4GBs in their laptops unless they actually need the 3.0GB to 3.5GB that they may actually be able to use from that installation.)

For a better explanation see for example these:
http://h20331.www2.hp.com/Hpsub/down...%2003Nov05.doc
http://www.asisupport.com/ts_4GB_memory_info.htm
http://chris.pirillo.com/2007/08/30/...nd-4gb-of-ram/

SmilingBoy

I don't think the description in the article you link is correct. I have the preference set to "programs", and my task manager reveals that system cache is 417 MB at the moment (out of 1GB total physical memory).

Still, I don't think more than 2GB is going to help the OP a lot when using XP. Don't know about Vista.

SmilingBoy.

nkedel

2GB is definitely the sweet spot; 4GB isn't overkill, but unless the price has fallen a lot (last I checked it was still ~$300+ for 2x 2gb SO-DIMMs vs ~$80 for 2x 1gb) it is not worth it for laptops (for desktops, where the price difference is linear - 4x 1gb for ~$150 vs 2x 1gb for ~$75) it *is* worth it.

If you're getting a very high end system anyway, and an extra +$200 isn't much money relative to the cost of the machine, get 4gb, it'll save the trouble of upgrading later.

3gb isn't a very good option for a notebook, as that will run in single-channel mode since it's unmatched (for a desktop, 2x 1gb / 2x 512mb was an OK option back when 1gb dimms were the expensive ones; these days 2gb desktop chips are pushing affordability, so 6gb may similarly be a decent option soon.)

kanebear

Adding a stick of memory, perhaps. Yet one wants to be running in dual channel mode anyway. Have you looked at the incremental powerdrain from a 1gb soDIMM to a 2gb soDIMM? Negligible. I'll dig up the spec sheet I found.

As for the system cache, Microsoft also states you can't run XP off a USB drive, etc. Patently untrue as well. Those notes you cite came straight off the Microsoft KB entry... Try this; run Task Manager and click the Performance pane. Look at the Physical Memory area. The System Cache adjusts dynamically and that number is assuredly quite a lot larger than 10MB. It scales with RAM. Bigger cache=better performance.

ahallflyertalk

The "system cache" number in Task Manager represents the amount of physical memory in use, including that used by programs and the file cache. At the moment, my task manager shows about 800MB in use and a system cache of 816MB; "Available" is listed as 1.2GB, so clearly the cache isn't in addition to memory used by programs.

Once again, as shown by your case and mine, all your "unused RAM" isn't used by the cache. It just sits there, unused, until it is needed (if ever) by an application or process. Any RAM used by a file cache must be claimed and taken from free RAM but it's not very large. The point I've been trying to make here is: I could yank one of my 1GB sticks out and have only 1GB in this case and still have almost 200MB free and no change in performance (other than no longer having dual channel). But some people here seem to think that in my situation they ought to want 3GB or even 4GB if they could. But you wouldn't even notice the difference - except for more disk space required to hibernate, more time to hibernate and resume. The cache file wouldn't be any bigger, because it's based on the applications I have open, not on available RAM.

Now, if I start editing a 12.8MP image from my camera, I'll quickly start eating RAM and may eventually start to use almost my 2GB. But I suspect most people here aren't doing that. They think "more RAM is always faster no matter what" and it's just not. Your computer will be slow if it doesn't have enough RAM, but once it has "enough" you can waste your money buying more than you'll ever use. Totally depends on how you use your computer.