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PC2-5300 or PC2-6400?
Posted: Sat Jul 21, 2007 11:23 am
by phongdt
My x61 currently have 1 x PC2 5300 DDR2 667 1GB. Now, I want to upgrade the memory, so which one should I go with? PC2-5300 DDR2 667 or PC2-6400 DDR2 800?
Running 667 and 800 at the same time, will there be any issue? Or any performance improve?
Re: PC2-5300 or PC2-6400?
Posted: Sat Jul 21, 2007 4:35 pm
by archer6
phongdt wrote:My x61 currently have 1 x PC2 5300 DDR2 667 1GB. Now, I want to upgrade the memory, so which one should I go with? PC2-5300 DDR2 667 or PC2-6400 DDR2 800?
Running 667 and 800 at the same time, will there be any issue? Or any performance improve?
To take advantage of the dual channel functionality of the processor it's important to use the same speed ram as what is in your machine now. So in your case you would want to install a memory module that is PC2 5300 DDR2 667. It will make your computer run at it's fastest speed. If you use 800 then it will actually slow the computer.
Posted: Sat Jul 21, 2007 4:38 pm
by wpj
I installecd 2 kingston 2GB chips 5300-667 works perfecto
Posted: Sat Jul 21, 2007 7:41 pm
by phongdt
Thanks a lot for your advise.
Posted: Fri Jul 27, 2007 11:49 am
by archer6
Glad to help out.
This is a great forum that has certainly been beneficial to me in the past and I'm more that happy to give back.
Enjoy your ThinkPads!
Cheers...

Posted: Fri Jul 27, 2007 8:22 pm
by Antioch
Uhm. So the FSB is at 800MHz for the X61's right? In my case I'm replacing the 512Mb RAM that comes with the machine and I'm wondering if it's worthwhile to get PC2-6400 (DDR2 800) RAM or stick with PC2-5300 (DDR 667) RAM like Lenovo ships it with?
I believe the FSB to DDR speed matching offers the highest performance, so I wonder why Lenovo only uses DDR2 667?
Edit: Does the X61 BIOS allow you to run the RAM at DDR2 800Mhz, or is it locked at 677Mhz?
Posted: Sat Jul 28, 2007 7:22 am
by mfbernstein
You'll get no performance improvement from DDR2 800 memory, unless you're overclocking your machine somehow. Even though the Santa Rosa FSB is 800MHZ, the memory controller is set to only run at 533MHZ or 667MHZ. This is an Intel chipset limitation, not a Lenovo one.
Posted: Sat Jul 28, 2007 2:57 pm
by archer6
mfbernstein wrote:You'll get no performance improvement from DDR2 800 memory, unless you're overclocking your machine somehow. Even though the Santa Rosa FSB is 800MHZ, the memory controller is set to only run at 533MHZ or 667MHZ. This is an Intel chipset limitation, not a Lenovo one.
Well Said......100% accurate.