Can I mix different memory speeds (PC2100/PC2700)?

[Julianne]

I currently have 512mb ram in my PC. I know from the motherboard manual that it's DDR SDRAM but the manual just says it supports PC2100 and PC2700 so I've no idea which is installed (From what I can remember it's PC2100).

I want to buy another 512mb and have ordered the PC2700 variety as it's supposed to be faster. Now I'm wondering whether this is OK or whether I should have saved a little money and gone for the slower PC2100.

Will having two different speeds of ram cause conflicts? Will it cause the PC2700 to run at the slower speed of the PC2100? If so, I think I'll change my order before it's too late.

I'd be grateful if someone could confirm the situation for me - many thanks.

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[paparazi]

I take it that you have a 266fsb CPU?
Yes the new PC2700 will just run at the slower speed.
As far as conflicts go, well it's always advisable to buy matching modules but not always possible when it is bought at differant times and at differant places, you always run the risk that two modules won't like working together but that applies to the same speed as well so there is always a small risk.
I have found that the easiest way to check if they are performing well together is to carry out a before and after benchmark, if things aren't working properly there is usually a big hit 10/25% drop.
Can't see the point in buying older memory types when the prices are about the same.
Martin

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[cdogg]

So did you check your PC's BIOS? When you first turn it on, the POST screen should be one of the first things you seen before Windows starts loading. On that POST screen, look for line that tells you what key to use to get into the BIOS or system setup. Usually it's F1, F2, DEL, or ESC.

You can also download free tools off the net like Belarc Advisor or CPUID to get more information on your specs.

The price difference between the two speeds shouldn't be all that bad. If you don't have the time to check, then definitely go with PC2700 which will clock itself down to match what's in your system.


~cdogg
[tab]"All paid jobs absorb and degrade the mind";
[tab][tab]- Aristotle
[tab][navy]For general rules and guidelines to get better answers, click here:[/navy] faq219-2884

 

[AckNack]

I suggest you put the slower module in the first slot on the motherboard.

The BIOS is supposed to read all the memory modules and run them all at the slowest speed, but sometimes the first module gets read and that's the speed that all of them get run at.

So if you have the faster one in the first slot, and this happens, then the motherboard will try to run the slower one at the faster speed, which isn't good.

AckNack

http://www.diypctech.com

 

[ceh4702]

Assuming your computer can actually run at PC2700 speeds you still have a problem. With memory that runs at two different speeds the computer will default to the speed of the slowest memory you have on the motherboard.

It is of somewhat limited value to have Memory that runs faster than the FSB speed of the Processor. The processor can not process it faster than the Processor FSB Speed.

If you do not like my post feel free to point out your opinion or my errors.

 

[Julianne]

Thanks everyone for your help. I've decided to play it safe and change my order to the PC2100 variety.

Ice hockey nostalgia at:

http://www.leevalleylions.co.uk

 

[cdogg]

Julianne,
Actually, the PC2100 choice is not the safer of the two. The reason? Because if you have PC2700 memory in the system and the FSB is set to 333MHz, then there's a chance your motherboard might attempt to overclock the PC2100 chip.

The alternative was going with PC2700 which would cover BOTH speeds of 266MHz and 333MHz.


~cdogg
[tab]"All paid jobs absorb and degrade the mind";
[tab][tab]- Aristotle
[tab][navy]For general rules and guidelines to get better answers, click here:[/navy] faq219-2884

 

[cdogg]

ceh4702,

I'm not sure what your post is about. The issue here isn't to use faster memory than what the system needs. Instead, it's to make sure you have fast enough memory in case the system already has PC2700 installed. The idea is that no matter what memory is in there, buying PC2700 will be a close guarantee that it will run at the right speed (clocking itself to match what's already there).

Of course, the best solution is to check before you buy!



~cdogg
[tab]"All paid jobs absorb and degrade the mind";
[tab][tab]- Aristotle
[tab][navy]For general rules and guidelines to get better answers, click here:[/navy] faq219-2884

 

[Julianne]

I've changed my order back to the PC2700. I decided to try SiSoft Sandra and that has confirmed I have PC2700 installed. Just a shame that neither Fujitsu-Siemens, nor their website, nor their spares people nor the company that handles their online sales could give me this information!

Ice hockey nostalgia at:

http://www.leevalleylions.co.uk