Clem24

Hi, I am trying to upgrade my ram but am getting a bit confused.

Q1. I have heard that the RAM speed has to be the same or higher than the FSB and that the RAM speed will slow down to the FSB speed if the FSB speed is slower. By the FSB speed am I right in thinking that it is the real clock speed I should be looking at and not the effective clock speed?

Q2. I have heard that windows 32-bit operating systems can only recognise 3gb or 3.5gb of memory. By the sounds of things the computer only uses the extra 500mb for temporary files when the RAM is full rather than using the hard drives' memory. Is this correct or can someone explain further on this? I am asking this question as I am not sure whether to upgrade to the full 4GB or just to 3GB instead if the extra is not going to be used or be used infrequently.

Q3. I have dual channel memory with 4 banks. Only 2 banks are being used at the moment by two 512mb modules. I have been told that my motherboard has 2 channels (maybe that is why it is called dual channel memory or maybe because you have to install two modules the same I dont know), one channel is being used by the two modules that are in there already and the other channel is obviously free. I understand that I need to get the memory kits that use exactly the same types of RAM but if I use faster RAM than is already in my computer will it slow down to the speed of the slower RAM even though it is using a different channel?

Q4. If I was to upgrade my motherboard at a later date would I be able to move my old RAM over to it if the FSB speed on it is faster than my RAM? If so would the FSB speed slow down to my RAM speed?

Q5. My motherboard supports faster RAM than the speed of the FSB would there be any advantage in installing faster RAM if it is going to be slowed down by the FSB? If not why does my motherboard support faster RAM if it is just going to be slowed down to the FSB speed anyway? Is the FSB speed maybe determined by the processor? and my motherboard supports faster RAM incase the processor is upgraded?

I would appreciate it if people could please reply with decent answers and not try to overcomplicate them too much.

It would be really helpful if people could put the question number next to the question that they are answering.

Thanks in advance.

tecknomage

Your list is only partly true.

First, any written specs MAY be missing critical data.

Any RAM you buy for a particular PC must be an exact match to the motherboard. The manufacturer of the motherboard IS the LAST word on what RAM you can use.

A better way to see what RAM you need is to use 4AllMemory's [Check My System] applet.

Using this will download a small, temporary, applet that will read your motherboard and return a WEB page showing you what you have (installed RAM & open slots), and what memory upgrades match your motherboard.

If your motherboard is a brand-name (like my MSI), the page will list the motherboard manufacturer's part number.

I suggest you use 4AllMemory to see what you actually need. Also, suggest you print the page and save for the future.

Of course, you don't have to buy from 4AllMemory but at least you'll know what you actually need.

Being the IT Tech where I work, I've use this method for 2 memory upgrades, and was pointed to this site by Corporate IT. They bought the memory from 4AllMemory (saved money from normal source).

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Tecknomage
Computer System Specialist
IT Technician

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Clem24

I have been to crucial and done this but I was trying to understand how it works. It gives me a few options on the types of RAM I can use which I already know because I have information on which RAM my motherboard supports already.

I know which RAM will work in my computer but I need to know the pro's and cons of using slower RAM as oppose to the newer modules i.e. the newer RAM is more expensive so I don't want to pay alot for it if it will just slow down to the FSB speed. Just because it works doesnt mean it is the best type to use.

The information that the website give mes on which RAM to buy isn't entirely helpful as it tells me that I can upgrade my computer to upto 8gb which when I use a program to look at my motherboard properties it says it can only support upto 4gb and also windows can apparently only see 3gb or 3.5gb of RAM anyway so that would be pointless, also It tells me to use the fastest RAM that my motherboard supports which if it slows down to the bus speed of the FSB is not worth buying and paying the extra for.

If anyone can answer the questions that I've asked above in the original post it would be very helpful and then I could work it out for myself.

wrench97

What brand model motherboard do you have? If OEM Brand, Model of the PC

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adplante

Not much help to your problem probably, but in response to question number 2

As long as your mobo supports 4gb of ram, you can install it just fine. Windows just stores that extra 500gb for temp files, as you said, and it wont display the full 4gb, your system will only register 3.5 or 3gb of useable ram.

Clem24

Dell Dimension 5150/E510 motherboard

FSB Real clock 200 MHz(QDR)
FSB Effective clock 800MHz

Supported memory types DDR2-400 SDRAM, DDR2-533 SDRAM, DDR2-667 SDRAM
Maximum Memory Amount 4 GB

Current memory in my computer = 2 x 512mb DDR2-400(200MHz) DDR2 SDRAM

Memory Controller Type Dual Channel (128-bit)

Hope this helps.

Clem24

Thanks adplante that has cleared up question 2 which would make me probably more likely to go for 3gb of RAM instead of 4gb, although I need to know if the RAM I've got in my computer will slow down any new faster RAM that I put in or if the FSB speed will slow any faster RAM that I put in.

Thanks

wrench97

In order for it to run in dual channel mode you'll need to have matched RAM, your motherboard supports 1Gig modules. if you want to run 3gig it will but not in dual channel mode.
As for the speed if you are going to buy matched modules I would buy 2 1Gig at 533Mhz
or if you want to reuse your existing buy 2 1gig at 400Mhz, however you will be better off having all modules matched.

As for moving it to another board in the future I wouldn't count on it the speeds are changing.

"Addressing Memory With 4-GB Configurations

Your computer supports a maximum of 4 GB of memory when you use four 1-GB DIMMs. Current operating systems, such as Microsoft® Windows® XP, can use a maximum of 4 GB of address space; however, the amount of memory available to the operating system is less than 4 GB. Certain components within the computer require address space in the 4-GB range. Any address space reserved for these components cannot be used by computer memory."
From the manual.

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adplante

Wrench,

Off topic, but what are the benifits of running dual channel? and how would someone go abuot doing that? Is there any bios setup or anything like that required to run dual channel?

wrench97

[quote=adplante;1566967]Wrench,

Off topic, but what are the benifits of running dual channel? and how would someone go abuot doing that? Is there any bios setup or anything like that required to run dual channel?[/QUOTE

A decent explanation here.
http://en.wikipedia.org/wiki/Dual-channel_architecture

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