Will I see an increase in speed from 384MB to 512MB of RAM

[iann070]

My ThinkPad T21 has always had one stick of 128MB RAM and I have just installed an additional 256MB stick to bring it up to 384MB.
I knew it would improve thing a little but I was quite surprised at how quickly it now boots to Win XP Pro and runs a lot quicker.

So now I'm thinking of replacing the original 128MB stick with another 256MB stick to get the maximum 512MB.

Will increasing the RAM by another 128MB improve things even more, or will I be just wasting my money.

[djpharoah]

Well the performance will not change by a noticable amount but atleast your maxing out the ram oon your laptop. That means you can run more apps at the same time.

[dsigma6]

how much is available of your 384?

[ambientscape]

My ThinkPad T21 has always had one stick of 128MB RAM and I have just installed an additional 256MB stick to bring it up to 384MB.
I knew it would improve thing a little but I was quite surprised at how quickly it now boots to Win XP Pro and runs a lot quicker.

So now I'm thinking of replacing the original 128MB stick with another 256MB stick to get the maximum 512MB.

Will increasing the RAM by another 128MB improve things even more, or will I be just wasting my money.

I would suggest you go ahead with the 512MB. My girlfriend had a T22 with 512MB......and the start up is marvellous with only 4200rpm drive. Would highly recommend...since you are using Win XP.

[Thinkpaddict]

I might be wrong, but I think that increasing memory won't speed up boot times (unless you have so little memory that you are paging right away at startup time). It might also actually increase the time to go in and out of hibernation.

However, having lots of memory is obviously good in general. If you need memory and your RAM is full you are going to be paging to disk, and that really can hurt performance. If you could avoid paging to disk you might also potentially increase the lifetime of your HD.

[christopher_wolf]

Just a quick note; increasing your memory capacity doesn't add much to the time it takes to suspend/hibernate/resume. Windows takes an image "shot" of the active memory contents, then compresses and indexes them, then goes into the assigned sleep state, it will not write a simple one-to-one-only image of all memory contents included unused portions as placeholders (in the case of hibernation, it will write the memory contents to the hiberfile.sys on the HDD). If, however, you add more memory and *then* use more of it than you did before you upgraded, such as using 1GB after you added a RAM module as opposed to using 512MB before the addition, then it will take longer. The time it takes to enter such a sleep state depends on the number of active threads, processes, and jobs running at the time the system recognizes the shutdown/sleep hook and not so much on the total memory capacity available to the system. As such, the suspend process is affected more by the behaviour and cleanup of those processes when they receive the signal to cease-and-save.

[dsigma6]

chris, at this point i'd believe anything you write.

[christopher_wolf]

Thanks, but it took quite a bit of research for me when I first wondered why, then again when the issue came up again a few months back in some threads. This is also discussed in a Microsoft article and various other online system analysis articles.

Here is a place to start; http://www.chelper.net/windows_xp_kerne ... ements.htm

and here

http://www.microsoft.com/technet/prodte ... pperf.mspx

Standby is a low power state from which you can resume working with your desktop and applications intact. When using standby the contents in memory are kept in volatile RAM. Many newer laptops resume from standby in less than two seconds. Hibernation saves the contents in memory to disk in compressed form, allowing the computer to be turned completely off. Again, you can resume with your desktop and applications intact. Many newer laptops resume from hibernate in 20 seconds to 30 seconds, but the actual time it takes to do this is heavily dependent upon the contents in memory at the time you choose to hibernate your computer.

*Emphasis added*

There are also some more articles that go into much more depth (including a very good one by a BSD/Linux/Windows developer as to the kernel memory handling routines during sleep state transitions and this very subject), but I would have to look through my bookmark archives for those. I also posted the links to them in the other threads on this.

[Thinkpaddict]

Just a quick note; increasing your memory capacity doesn't add much to the time it takes to suspend/hibernate/resume. Windows takes an image "shot" of the active memory contents, then compresses and indexes them, then goes into the assigned sleep state, it will not write a simple one-to-one-only image of all memory contents included unused portions as placeholders (in the case of hibernation, it will write the memory contents to the hiberfile.sys on the HDD). If, however, you add more memory and *then* use more of it than you did before you upgraded, such as using 1GB after you added a RAM module as opposed to using 512MB before the addition, then it will take longer. The time it takes to enter such a sleep state depends on the number of active threads, processes, and jobs running at the time the system recognizes the shutdown/sleep hook and not so much on the total memory capacity available to the system. As such, the suspend process is affected more by the behaviour and cleanup of those processes when they receive the signal to cease-and-save.

Great information. It makes sense that the time to enter standby/hibernation is influenced quite a bit by cleanup operations of the active processes. I also suspected (but until now didn't know) that inactive memory is not saved.

What would happen if two computers using 1 Gb of memory (one with 512Mb of physical RAM, thereby having an additional 512Mb of paged memory on disk, and the other having 1Gb of physical memory and potentially not using any paged memory) go into hibernation? Would the OS have to process paged memory on the 512Mb computer or not? If it doesn't, then the OS would have to save to disk only 512Mb in one computer as opposed to 1Gb in the other. However...this apparent (I stress the word apparent) advantage of the computer with 512Mb RAM would be obviously offset by the fact that the 1Gb computer would be much faster when running (potentially no paging).

By the way, do you teach at Berkeley? It sounds like you might.

Regards.

[kstuart]

Going back to the original topic...

When you increased from 128mb to 384mb, you tripled the memory of the laptop, ie a 200% increase. Also, you moved from a condition where the amount of memory was marginal for the operating system, to a condition where your memory is more than enough for the OS.

If you go from 384mb to 512mb, you will only increase by a third, ie 33%. So, the amount of increase is one sixth the previous increase.

So, it will be a much milder increase.

If you don't have more than 3 or 4 windows (apps) open at a time, then you are unlikely to notice the difference.

Which is why my T22 will stay at 384mb for the immediate future.