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Topic: ultimate guide to ram and virtual memory :)

This topic is old and might contain outdated or incorrect information.

sbangsPRO InfinityMember since 2004
In the next series of guides I will be talking about the key parts of a computer which affect the speed of virtual dj and your computer
I have learnt this information recently on a course called Compita A+
If you would like to learn more about building and supporting computers this is a good course





And some tips to configure them to there highest performance

Part one

Ram and Virtual Memory

To get the most out of your pc you need good memory as all audio is loaded into ram before playing in virtual dj
Also the more ram you have the larger the songs you can load and the faster it will load
Also you will be able to multitask more easily
Also as I mentioned in my guide about broadcasting the more ram you have theoretically the more listeners you can have when you use your pc as a server
http://www.virtualdj.com/forums/59741/General_Discussion/The_Ultimate_Guide_to_Broadcasting_With_Virtual_Dj_).html

to learn how much ram you have in your computer the simplest way to find this out is to
go to my computer and rightclick and press properties

you will see at the bottom of the window the amount of ram you have
lets take a moment to look at the common types of ram

here are the standard pc types of ram
SDRAM (Synchronous DRAM)
Almost all systems used to ship with 3.3 volt, 168-pin SDRAM DIMMs. SDRAM is not an extension of older EDO DRAM but a new type of DRAM altogether. SDRAM started out running at 66 MHz, while older fast page mode DRAM and EDO max out at 50 MHz. SDRAM is able to scale to 133 MHz (PC133) officially, and unofficially up to 180MHz or higher. As processors get faster, new generations of memory such as DDR and RDRAM are required to get proper performance.

DDR (Double Data Rate SDRAM)
DDR basically doubles the rate of data transfer of standard SDRAM by transferring data on the up and down tick of a clock cycle. DDR memory operating at 333MHz actually operates at 166MHz * 2 (aka PC333 / PC2700) or 133MHz*2 (PC266 / PC2100). DDR is a 2.5 volt technology that uses 184 pins in its DIMMs. It is incompatible with SDRAM physically, but uses a similar parallel bus, making it easier to implement than RDRAM, which is a different technology.

DDR is easily identifiable by the two notches in the side
Rambus DRAM (RDRAM)
Despite it's higher price, Intel has given RDRAM it's blessing for the consumer market, and it will be the sole choice of memory for Intel's Pentium 4. RDRAM is a serial memory technology that arrived in three flavors, PC600, PC700, and PC800. PC800 RDRAM has double the maximum throughput of old PC100 SDRAM, but a higher latency. RDRAM designs with multiple channels, such as those in Pentium 4 motherboards, are currently at the top of the heap in memory throughput, especially when paired with PC1066 RDRAM memory.

Dram is easily identifiable as it only has one notch on the side
DIMMs vs. RIMMs
DRAM comes in two major form factors: DIMMs and RIMMS.
DIMMs are 64-bit components, but if used in a motherboard with a dual-channel configuration (like with an Nvidia nForce chipset) you must pair them to get maximum performance. So far there aren't many DDR chipset that use dual-channels. Typically, if you want to add 512 MB of DIMM memory to your machine, you just pop in a 512 MB DIMM if you've got an available slot. DIMMs for SDRAM and DDR are different, and not physically compatible. SDRAM DIMMs have 168-pins and run at 3.3 volts, while DDR DIMMs have 184-pins and run at 2.5 volts.
RIMMs use only a 16-bit interface but run at higher speeds than DDR. To get maximum performance, Intel RDRAM chipsets require the use of RIMMs in pairs over a dual-channel 32-bit interface. You have to plan more when upgrading and purchasing RDRAM.
Memory Speed
SDRAM initially shipped at a speed of 66MHz. As memory buses got faster, it was pumped up to 100MHz, and then 133MHz. The speed grades are referred to as PC66 (unofficially), PC100 and PC133 SDRAM respectively. Some manufacturers are shipping a PC150 speed grade. However, this is an unofficial speed rating, and of little use unless you plan to overclock your system.
DDR comes in PC1600, PC2100, PC2700 and PC3200 DIMMs. A PC1600 DIMM is made up of PC200 DDR chips, while a PC2100 DIMM is made up of PC266 chips. PC2700 uses PC333 DDR chips and PC3200 uses PC400 chips that haven't gained widespread support. Go for PC2700 DDR. It is about the cost of PC2100 memory and will give you better performance.
RDRAM comes in PC600, PC700, PC800 and PC1066 speeds. Go for PC1066 RDRAM if you can find it. If you can't, PC800 RDRAM is widely available.
CAS Latency
SDRAM comes with latency ratings or "CAS (Column Address Strobe) latency" ratings. Standard PC100 / PC133 SDRAM comes in CAS 2 or CAS 3 speed ratings. The lower latency of CAS 2 memory will give you more performance. It also costs a bit more, but it's worth it.
DDR memory comes in CAS 2 and CAS 2.5 ratings, with CAS 2 costing more and performing better.
RDRAM has no CAS latency ratings, but may eventually come in 32 and 4 bank forms with 32-bank RDRAM costing more and performing better. For now, it's all 32-bank RDRAM.
The more you pay for your ram the better the latency
Understanding Cache
Cache Memory is fast memory that serves as a buffer between the processor and main memory. The cache holds data that was recently used by the processor and saves a trip all the way back to slower main memory. The memory structure of PCs is often thought of as just main memory, but it's really a five or six level structure:
The first two levels of memory are contained in the processor itself, consisting of the processor's small internal memory, or registers, and L1 cache, which is the first level of cache, usually contained in the processor.
The third level of memory is the L2 cache, usually contained on the motherboard. However, the Celeron chip from Intel actually contains 128K of L2 cache within the form factor of the chip. More and more chip makers are planning to put this cache on board the processor itself. The benefit is that it will then run at the same speed as the processor, and cost less to put on the chip than to set up a bus and logic externally from the processor.
The fourth level, is being referred to as L3 cache. This cache used to be the L2 cache on the motherboard, but now that some processors include L1 and L2 cache on the chip, it becomes L3 cache. Usually, it runs slower than the processor, but faster than main memory.
The fifth level (or fourth if you have no "L3 cache") of memory is the main memory itself.
The sixth level is a piece of the hard disk used by the Operating System, usually called virtual memory. Most operating systems use this when they run out of main memory, but some use it in other ways as well.
This six-tiered structure is designed to efficiently speed data to the processor when it needs it, and also to allow the operating system to function when levels of main memory are low. You might ask, "Why is all this necessary?" The answer is cost. If there were one type of super-fast, super-cheap memory, it could theoretically satisfy the needs of this entire memory architecture. This will probably never happen since you don't need very much cache memory to drastically improve performance, and there will always be a faster, more expensive alternative to the current form of main memory.
The more cache memory you have the faster your processor will run
now each computers motherboard takes a specific type of ram like enzymes in biology only the right type of ram will fit in the slot
to work out what ram your pc takes use this free tool
http://www.crucial.com/systemscanner/
this tool will tell you what memory is installed
how much your machine will support and what upgrades are available for your pc

the more ram you have the faster your machine will operate until it reaches its peak.
Its important to remember that your computer runs at the speed of the lowest component
So if your disk drive is only 30,000 rpm it will be slower than you could be on a 75,000 rpm
Rpm (rotations per minute)
So its important when upgrading to upgrade all your main components if possible

installing ram on a desktop pc

there are two general types of ram slot in a desktop pc

the first type requires that you put the ram in the slot and then pop it in

the second more common slot requires you to press the slot downwards

you will find the slot usually on the right of your motherboard this varies via boards

most pcs have 4 ram slots with rimm memory all ram slots must be filled you can buy blanking panels to complete the circuits
With laptops it’s a slightly different story
they take sodimm memory which is a reduced form of ddr
many laptops are a sealed unit which you have to send back to the manufacturer to be upgraded
call them and they will advise on prices and upgrades available , your local pc repair shop can help also
if you are lucky and have a laptop that has access panels or a removable keyboard

for removable keyboards
for access panels you simply slot the ram in

most laptops have 2 ram slots
when you buy ram from will also give u a manual for more in-depth information for your model of pc[/colour]

virtual memory
Virtual memory is a feature of windows 2000 + which allows extra memory to be simulated as a file on your pc called the swap/page file , the larger this is the more stable your pc will be
To learn how big your page file is and how well it is proforming press ALT + CONTROL + DEL


When the physical memory (RAM) is used up, XP looks to the paging file for help by paging out its excess requirements. The timing of when this occurs is based on your hardware and the load the computer is experiencing. A sure sign that your computer is under excessive load and making use of the page file is when you experience 'disk thrashing', or a continual writing of data to and from the hard drive. The information that is most useful relating to page files is found in the Physical Memory (K), Commit Charge (K), and Kernel Memory (K) sections. The Totals section is more useful to developers and except for the Processes totals won't enter into this discussion. Read through the explanations below and then we'll see how they apply to the page file.
Commit Charge (K) - The values displayed in this section are in kilobytes (K/KB). To convert to megabytes (MB), divide by 1024.
• Total: The total amount of physical (RAM) and virtual (Page File) memory currently being used by the operating system and all open applications. This value will increase as applications and files are opened and decrease when they are closed. Commit Charge is also displayed in the lower right side of Task Manager. Dividing the Total (183692) by conversion factor of (1024) yields 179 MB, or the same amount shown lower right by Commit Charge: 179M/1878M.
• Limit: The total amount of physical (RAM) and virtual (Page File) memory that is currently available to the operating system and applications. There are two ways to change this value; install additional RAM or increase the size of the page file. Dividing the Limit (1923908) by conversion factor of (1024) yields 1878 MB, or the same amount shown lower right by Commit Charge: 179M/1878M
• Peak: A combined measure of the physical (RAM) and virtual (Page File) memory that has been used during the current windows session. If the Peak value approaches the Limit value it's a good indication the system needs more memory.
Physical Memory (K) - The values displayed in this section are in kilobytes (K/KB). To convert to megabytes (MB), divide by 1024.
• Total: The total amount of physical (RAM) memory installed in the computer. Dividing the Total (785908) by conversion factor of (1024) yields 768 MB, or the same amount verifiable by right clicking on My Computer then clicking Properties to open the System Properties sheet.
• Available: The total amount of physical (RAM) memory that XP will allow programs to use before it switches to virtual (Page File) memory. By default, XP reserves a quantity of the physical memory for additional demands rather than depleting it totally before accessing the page file. Dividing the Total (520136) by conversion factor of (1024) yields 508 MB. Subtracting the 508 MB Available from the 768 MB Total shows XP has reserved 260MB at this particular point in time.
• System Cache: The amount of physical (RAM) memory that is currently being used to store recently accessed programs and data. By default, Windows XP uses as much physical (RAM) memory as possible to cache programs and data. Dividing the Total (550836) by conversion factor of (1024) yields 537 MB available to the system cache. This one setting alone demonstrates the value of installing extra physical memory. XP automatically releases the system cache memory when it's needed by the operating system or other programs.
Kernel Memory (K): The kernel manages the basic operations of the operating system so it's no surprise that it demands memory to accomplish its function. The values displayed in this section are in kilobytes (K/KB). To convert to megabytes (MB), divide by 1024.
• Total: The total amount of physical (RAM) memory that XP uses for core component operations, including drivers for installed devices. Dividing the Total (64372) by conversion factor of (1024) yields 63MB, or approximately 8% of the installed total. On the example machine I'm using for this discussion, the 63MB is a small portion of the 768 MB total installed physical (RAM) memory. However, on a machine that only has 128MB of RAM, the percentage soars to 49% of the installed total. It's easy to see why the recommended minimum RAM for XP is 128MB and 64MB is the absolute minimum supported. Less than 64MB would not be able to support the core components.
• Paged: The total mount of physical (RAM) memory that XP core components are using that are currently mapped to virtual (Page File) memory. Dividing the Total (48144) by conversion factor of (1024) yields 47MB.
• Non-Paged: The total mount of physical (RAM) memory that XP core components are using that cannot be mapped to virtual (Page File) memory. Dividing the Total (16228) by conversion factor of (1024) yields 16MB. Adding the total of Paged (47MB) and Non-Paged (16MB) yields 63MB, or the total Kernel Memory required for core and driver operations in Windows XP.

To change the size of the virtual memory paging file


You must be logged on as an administrator or a member of the Administrators group in order to complete this procedure. If your computer is connected to a network, network policy settings may also prevent you from completing this procedure.

Step one go to my computer

Step two right click properties
Step Three go to the advanced tab

Step four press settings in the box called proformance

You will now see this screen
http://www.askdavetaylor.com/0-blog-pics/windows-xp-swap-config.jpg" border="0">
now there are 3 options 1. a custom size 2. a system managed size 3. no page file!

1. a setting between 500-2gig is good in machines with more ram use less , if you have less ram but a large hard rive go for about 1-2 gigs
2. a system managed page file windows adjusts the file as needed this is good if you are unsure what settings to choose but it can lead to some problems when windows doesn’t work it out correctly
3. having no page file is for systems with large amounts of ram which don’t need page files , I recommend however you keep a small page file just incase of about 200 meg

Some final tips

there are tools to clear out your ram when it starts to clog up
such as http://www.freedownloadscenter.com/Best/ram-cleanup.html
and this website shows how to clear your page file on shut down this will help it to proform better
http://netsecurity.about.com/od/windowsxp/qt/aa071004.htm
shut your machine down when you arnt using it this refreshes your ram
if you use a machine constantly with out ever shutting it down it will get slower and slower
defrag your page file this can be done with www.diskkeeper.com (disk keeper 2007)
I hope this proves useful for you
If you have any problems or need some advise
Send me an email at admin@skyfxlmedia.com :)

Posted Thu 16 Nov 06 @ 6:53 pm


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