Percentage of RAM usage

[ftpl]

Hi,

What is the maximum RAM usage percentage at which you're pc will still run smooth (fast, when multi tasking: surfing IE, office progs. WMP, UnRaring a bunch of DVD's etc.). That is to say around what RAM usage percentage is it recommandable to invest in extra RAM?

My PC

OS: W7 x64
RAM: DDR2-800 2x2GB
Processor: Intel Q6600
GPU: ATI Radeon HD3850
MB: P5Q Pro
RAM Percentage when MultiTasking (as described above): 63%
Superfetch: ON
Aero: ON

I hope to get some good answers on the question asked .

Greets

 

[GhislainG]

It will run fine until you reach 100% memory utilization and swapping starts to occur.

 

[ftpl]

Hi,

First of all thanks for the quick reply.

Is that really all there is to it?

If so, why do I seem to loose performace (speed) when doing all the task described above at once (amount of simultaneous UnRar jobs: 15) at 65% usage of RAM and very low (<10%) CPU usage?

 

[GhislainG]

Disk I/O probably is what's killing performance. The CPU isn't working hard, but it does nothing while waiting on I/O. If you want to maximize performance while running 15 UnRar tasks (why so many at once?), then setup a RAID with as many hard disks or SSDs as possible and use a high performance controller with battery backup and a write back cache.

 

[ftpl]

Can you elaborate on the what you mean by I/O (Input/Output) in practical layman terms and why and how this affects the performance. Also can you describe a solution in a more abstract/theoretical terms so that I can choose the best (practical/economical) course of action by my self (or with the help of others of course)

Thank you very much in advanced.

 

[GhislainG]

To start with, are you really running 15 UnRar tasks at the same time? If so, then the bottleneck has to be the hard disk. The only solution to better disk performance is to use faster drives or SSDs (preferably Intel). Several hard disks in a RAID configuration always perform better than a single unit. The more hard disks you have in a RAID, the better the performance is. Such a solution will cost a significant amount of money, but it's worth it if you earn a living with your PC. What's your budget?

 

[ftpl]

Yes I really do UnRar this much at the same time (4.4GB files each, DVD's) and more (and this like burning at the same time, scanning pc for virus and things the like, while working on office and IE applications). I don't have a lot of time to spend in front of the PC so when I do, I try to get as much done as possible in the least amount of time possible. I like to personally see what's happening so I don't let any thing run automatically.
Ok so you say it's due to my HDD. PassMark Benchmarked my SamSung F1 Spinpoint at 74mb/s (average). Windows 7 scored it at 5.9. What speeds should I look for? What are the max. speed for HDD right now (I've seen the Spinpoint F3 runs at 125mb/s and is considered to be the fastest HDD right now).
My Budget for a an HDD or SSD is max of 150-200 Euros.
Do I need a fast Disk only for my OS and applications? If not when do I need to start looking at a faster Disk for my Files & Documents also?

Thank you again for helping me and I hope to get some more ;-)

Greetings

 

[GhislainG]

If that's all you can spend, then setup a few hard disks in RAID0 for your data. Just make sure that you perform backups on a regular basis because RAID0 is not as reliable as single disks, i.e., if one disk fails, then you lose all data. If you can't afford hard disks designed for RAID use, consider WD6401AALS or similar drives that are quite reliable.

 

[ftpl]

I'm not willing to set up Raid config. (because of all the hassle and problems regardless of the benefits).

Could you answer my other questions please:

What read/write speeds should I look for? What are the max. speed for HDD right now (I've seen the Spinpoint F3 runs at 125mb/s and is considered to be the fastest HDD right now).
My Budget for a an HDD or SSD is max of 150-200 Euros.
Do I need a fast Disk only for my OS and applications? If not when do I need to start looking at a faster Disk for my Files & Documents also?

Thank you again for helping me and I hope to get some more ;-)

Greetings

 

[GhislainG]

A hard disk that has a transfer rate of 125 MB/s means nothing if it's slow when being used in a multi-tasking environment (which is what you do). If you UnRar 15 files at the same time, you need a couple fast disks (SSDs probably are too small for what you do). Add whatever affordable hard disk is the fastest at what you're doing and split the tasks across your current disk and the new one. If you like the performance increase, then add another hard disk. That's what I do when disk I/O is a concern and that's why I install several hard disks in my servers.

If your goal is to get your CPU close to 100% busy, then you need to increase I/O performance significantly.

 

[ftpl]

Ok ok I see. Do you have any source of more info on this topic (title of a book, links etc.), something specific and concrete though, because the internet (via google) is a HUGE place. So if you know of anything that would be great.

Again thank you very much

Greets

 

[GhislainG]

More specifically what are you looking for? Disk benchmarks? If so, visit http://www.storagereview.com/. You can also look at Tom's and Anandtech where SSDs have been tested. If you can afford a large SSD (relatively speaking), go for it.

 

[ftpl]

No I was tlk about the workings of I/O (and how RAID can help this problem). Not really willing to set it up ... but if I can get alot of info on it's workings I could always change my mind ;-)

 

[GhislainG]

Start with http://en.wikipedia.org/wiki/RAID.

http://www.anandtech.com/showdoc.aspx?i=3532&p=1

http://www.anandtech.com/storage/showdoc.aspx?i=3087

http://www.tomshardware.com/reviews/x25-e-ssd-performance,2365.html

If you throw enough money at it, you'll get the performance that you need.

 

[sub mesa]

The more RAM you have, the less disk I/O you will have to do. Generally your applications should not use more than 50% of your memory, leaving the other 50% as file cache. That works excellent to reduce the disk I/O and random seeks which can slowdown a pc significantly.

For games, it might even be preferable to have 12GB+ RAM, to avoid having to read from disk after a warmup period. Once loaded, it'll never have to load that part from disk again; it'll stay in RAM. Until you reboot ofcourse, but if you run 24/7 and have lots of RAM this works nicely to increase overall system performance and responsiveness to user input.

 

[ftpl]

Thank you guys alot!

I'll be sure to do my home work.

If anybody has more tips and/or links to sources explaining the workings of I/O and the optimization thereof, please don't hesitate to post them. I'm sure it will help me and alot of other people looking to learn more and achieve ever increasing pc performance.

Thank you once again and take care!

 

[GhislainG]

Extracting files requires disk I/O and additional memory won't help. You only use 65% of 4 GB, therefore adding memory isn't very useful. Large files are read from the hard disk and written back to it; memory is used as a buffer only. Faster hard disks will provide more benefits. I also have systems with 8 GB and a Q6600 and extracting files doesn't increase memory utilization, but it keeps the hard disks or the LAN very busy.

Before going out to get an additional 4 GB of memory, you should read http://www.tomshardware.com/reviews/memory-module-upgrade,2264.html.

 

[sub mesa]

Yeah but since HDDs suck at any non-sequential performance level, and SSDs are too expensive for many still, the RAM is a good way to limit disk access to prevent slowness.

If you're using disk access sequentially that's going to be fast but many times background I/O will make the access pattern non-sequential and the performance will drop from 100MB/s to 1-10MB/s in case of HDDs. If you had enough RAM and had an initial "warm up period" - the harddrive would only be used for write I/O not for read I/O. The RAM serves both as a cache and a buffer.

 

[sub mesa]

Oh and that article isn't the best i've seen; avg FPS testing is useless; its min FPS that counts.

In my own case, having 4GB RAM is not enough to prevent the min FPS from dropping to 0.9FPS in world of warcraft, which in itself only uses 1GiB RAM; but with a VM running (another 1GiB RAM) there's only 1.5GiB left for disk cache which means 'hickups' now and then; where the FPS is like zero for a fraction of a second. That's where the very low min-FPS comes from. After closing the VM and freeing up memory its already 33.9fps, while the average FPS is always against 59.9FPS (60fps being the limit as its tied to my refresh rate).

Benchmarks don't always uncover the truth.