Virtual Memory Optimization Guide!

[Dashken]

Even today, virtual memory is still very important component of the operating system. No matter how much memory you have, there is always a need for virtual memory. Therefore, its performance is of great importance. Optimizing the virtual memory system will greatly improve the performance of the computer.

Today, we will take an in-depth look at virtual memory, what it really is and how to optimize it! In this edition, we will also take a thorough look at the differences between swapfile and paging file as well as making a contiguous paging file. Come and check out the definitive Swapfile Optimization Guide!

Here are the updates:-

• Added discussion on differences between swapfile and paging file.
• Corrected all references to the virtual memory file as paging file, instead of swapfile.

Link : Virtual Memory Optimization Guide Rev. 4.0!

[News Writer]

The guide has just been updated!

Even today, virtual memory is still very important component of the operating system. No matter how much memory you have, there is always a need for virtual memory. Therefore, its performance is of great importance. Optimizing the virtual memory system will greatly improve the performance of the computer.

Today, we will take an in-depth look at virtual memory, what it really is and how to optimize it! In this edition, we will also take a thorough look at moving paging file to the outer tracks as well as the pros and cons of making a very large paging file. Come and check out the definitive Virtual Memory Optimization Guide!

Here are the updates:-

• A thorough look at moving paging file to the outer tracks.
• The pros and cons of making a very large paging file.

Link : Virtual Memory Optimization Guide Rev. 4.0!

[Viper007Bond]

I just use CachemanXP to manage my virtual memory and recover RAM.

I'll read the guide anyway though as I bet it's still really helpful.

[SmartDrv]

Viper: Programs like that hinder things more than help. Windows will automatically manage the size of the cache if more memory is needed by applications. All you are doing is making the cache less effective.

Regarding the article:

What benchmarking have you actually done to show that your optimizations have any effect on the performance of the system? Many of the optimizations in this article seem to revolve around the assumption that a fragmented page file reduces performance. It also seems to stress that a dynamic page file reduces performance.

While some of the people on arstechnica (specificially in the NT Mojo subforum) can educate you way better than I can (such as in threads like this) a couple points worth mentioning are:

The page file is not read sequentially or completely but rather in chunks of up to 64K each. The chance of a single read requiring an extra seek are minimal. In fact the performance degradation due to fragmentation is overhyped in general.

Setting a good sized mininum on a page file isn't a bad idea. But there is no need to limit the maximum. Should the page file grow to meet demand and than shrink again, the original allocated portion will still be in a single chunk (again it probably doesn't matter much). Although your program may have run a bit slower, you avoided an "Out of virtual memory" condition which would be far worse.

[Viper007Bond]

Hmm...

*uninstalls it and reads the guide*

[Adrian Wong]

Hello SmartDrv!

Actually, this is still a work in progress. Right now, only part 2 of the guide has been posted. If my calculations are right, the complete guide will consist of about 39-40 pages.

So, there is actually a LOT more to virtual memory optimization than just defragmenting the paging file. It just happens that you are only reading the first two parts of the guide.

Yes, the new paging file system reads in chunks. But I don't think it's 64K. The last time I checked Microsoft's Knowledge Base, it was 4K chunks. So, performance degradation is not as severe as in the swapfile days. I think I mentioned this in the guide.

However, that does not mean that defragmenting the paging file won't improve its performance. Defragmenting the paging file keeps the paging file together. This reduces head seeks. And if you move the paging file to the outer tracks, that ensures maximum transfer rates from the paging file. All of it, not just some parts.

As for the maximum page file size, if you read the guide again, you will see that I recommend creating a semi-permanent paging file. In fact, I also mentioned that there is no way to create a true permanent paging file. Windows XP automatically extends the paging file if there is a need for more virtual memory.

[T8000]

As shown on the image, my swapfile is split up in 2 halves, even while it has its own partition and there is nothing in between of it.

I formatted the partition and recreated it, but it always splits up.

Why does this happen?

[SmartDrv]

Thanks for the quick response. I hope I didn't come off as being too negative but as I'm sure you understand there are a lot of "tweak" sites around that offer information that either does nothing or that actually hinders performance (i.e. most of those sites that tell you to edit low level memory management parameters)

While I don't see anything in your guide that would hinder performance, I do suggest a section about how changing what physical drive the page file is on is more important to overall performance than how fragmented it is. I imagine your next section will probably go over that mentioning things like how it's best to keep the page file on "fast but less busy" drives and how spanning the page file over multiple physical disks is good in some cases (i.e. SCSI) but bad in others (i.e. over 2 drives on the same IDE channel)

And as I suggest, if you need some more information, check out some of the past threads on the forum I posted. I'm not affiliated with the owners and am not trying to advertise that forum for them, however, there are a lot of smart people (Network Admins, Developers, Engineers, etc) mixed in the crowd. Some like DriverGuru seem to know so much about lower level functions of operating systems that it can make your head spin.

I look forward to your next update!

[Adrian Wong]

Originally Posted by T8000

As shown on the image, my swapfile is split up in 2 halves, even while it has its own partition and there is nothing in between of it.

I formatted the partition and recreated it, but it always splits up.

Why does this happen?

Hello T8000, as mentioned in the guide, Windows XP does not necessarily create a contiguous paging file. Even then, I agree. It's odd that it didn't create a contiguous paging file in an empty partition.

Don't worry though. You can easily defragment the paging file using Diskeeper or a similar utility.

[Viper007Bond]

Originally Posted by T8000

As shown on the image, my swapfile is split up in 2 halves, even while it has its own partition and there is nothing in between of it.

I formatted the partition and recreated it, but it always splits up.

Why does this happen?

Wow, that's a good idea.

I'm going to try to make mine use like 2 MB of space all of the time though as I should never have to use all of my GB of RAM... right?