Performance issues with 4 GB RAM (W2K)

[bepe27]

Hi all,

we are using HP XW 8000 workstations with W2k. They have 4 GB of physical RAM. Some of them slow down during the day. They have to be rebooted. Then it's ok again.

Taking away 2 of the 4 GB RAM prevents from slowing down, but that's no real solution.

All computers have 4 GB Swap on D:\, some have additional 4 GB Swap on C:\

Any ideas?

[jdharm]

All computers have 4 GB Swap on D:\, some have additional 4 GB Swap on C:\

!!!!!!

That swap file is waaaaay too big to be useful.

Try turning the size of that file down to something a little more manageable, like 256MB. The machines probably slow down because the swap file builds and builds over the course of the day and with a 4GB limit it finally gets to be worse than useless.

Theoretically, the purpose of a swap file is to give the system some place to hold data when it runs out of room in RAM. So the system is working from this file. Since the system can't work the data on a disk nearly as fast as in RAM the larger this file gets, the slower the machine will get in reading and writing data in this file.

With 4GB of RAM, you shouldn't need much of a swap file anyway.

Josh
<a target="_blank" href=http://www.jdharm.net>www.jdharm.net</a>

[bepe27]

jdharm,

we will try this, of course. But the machines with 2 GB physical RAM and 4 GB swap exceed the 4 GB virtual address space as well, but they are running fast.

Regards

[Brf]

You might have some bad memory sticks. We had one server that would run OK until its memory usage hit a particular value, then it would limp along until rebooted. Try swapping some sticks around to see if it makes a difference.

[bepe27]

Brf,

that might be a possible cause, but there are no crashes or hangs just a very low performance. On the other hand, this problem occurs on up to 50 computers. I don't believe that all of them have faulty memory.

But here is another additional info:

Although we have 4 GB RAM the system properties show only 3,5 GB (!?!)

[bepe27]

Hi jdharm,

we reduced the swap file down to 256 MB as you suggested. In fact the machines are running fast all the day, not slowing down anymore. But now another error occured: There is an application (for some technical calculations) which quits with the message "Not enough virtual memory".

What about other suggestions I've heard/read? One says to set the "DisablePagingExecutive" value to 1. Others say this trick doesn't work anymore. Again others say that memory might get fragmented, we should use some tool that runs every hour to defragment the memory. What do you think of that?

Regards

bepe27

[jdharm]

Well, I'd just be guessing here, but I'd think that running the defrag all the time would just add to the system load.

If turning down the swap file helped performance, then I'd think that this verifies that it was the original problem. So what I'd do is pick a few machines to experiment with and start turning it back up a little at a time. See if you can find the point where the error quites popping up and performance through the rest of the day doesn't suffer too bad.

I know this sounds low-tech and haphazard. But everyone's situation is a little unique in some way and sometimes it comes down to a matter of trial and error to find what works best for a given situation.

The only other thing that comes to mind would be to contact tech support for the application in question, see if there are any system requirements or limitations on this app. There may be some issues that this particular application has with your setup. It seems to me that an application shouldn't choke if it has 4GB of RAM to work with. That should be more than enough for practically anything. I can't imagine virtual memory even becoming an issue at this level. (Maybe I just don't understand how the system manages memory use.)

Josh
<a target="_blank" href=http://www.jdharm.net>www.jdharm.net</a>

[bepe27]

jdharm,

that's the way we will go on. If it shows that just this single application requests more virtual memory, then it seems clear that it's this applications "fault". If all other applications work well with 4 GB RAM and small pagefile of 256 MB (512 MB is too big) then OK.

Thank you very much for your help.

Regards

bepe27<P ID="edit"><FONT class="small">Edited by bepe27 on 10/24/03 07:04.</FONT></P>

[jdharm]

Glad I could help. Hope you get it sorted.

Josh
<a target="_blank" href=http://www.jdharm.net>www.jdharm.net</a>