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PC2-6400 (800MHz) running at pc2-5300 (667MHz)

  • Memory
  • RAM
  • Dell
  • Computers
Last response: in Memory
November 20, 2008 9:35:34 PM


First off i would like to say one thing... If i ever see Mr. dell of Dell computers i will kill him...

I looked all over the web for my problem and can't seem to find it. So i decided that it was time to make my first S.O.S post ever.

Here is my problem.

I purchased more ram for my computer. my computers has 2x 1 gig DDR2 PC2- 6400 (800MHz) I just got in my new ram 1x 2 gig DDR2 PC2 - 6400 (800MHz). Now when i installed the new ram the bios shows 4gigs. but the MHz has slowed to 667MHz. I have checked the new ram and made shore it was right and it is.

What i have dun to try to fix it

I made shore that the memory modules are match on the DIMM connectors according to the Manuel for my computer.

I have upgraded my BIOS to the latest build.

I have ran test on the memory. it past all the test.

i must be missing something. I will be very grateful for any help you can offer.

More about : pc2 6400 800mhz running pc2 5300 667mhz

November 20, 2008 9:50:39 PM

Some more info for you
I ran the new stick by it's self it runs at full speed 800mhz. but when i add one 1gig stick with it, it slows to 667. If i remove the new 2gig stick and place the old ones back in it runs at 800MHz. So now i am really confused.
November 20, 2008 10:08:06 PM

check and set the voltage in the bios to the manufacturers spec, then set the speed, manually, in the bios to the 800 mhz setting.
I had the same problem with a computer I just put together. The SPD settings on the RAM weren't read properly by the mobo; the voltage was .2 volts too low, and the frequency was off too. After I manually configured the memory, it worked just as expected. No errors, and a bit faster (1066mhz vs 800 mhz).
Related resources
a c 128 } Memory
November 20, 2008 10:17:03 PM

This may have to do with single versus double sided memory sticks, or a limitation of your board chipset. Too bad dell doesn't include a regular motherboard manual; many will give you the various memory options.
November 20, 2008 10:29:42 PM



I checked that like you asked but there is no option in the bios to change that or even see if that's the case :(  But when i run it by it's self it does run at full speed.

November 20, 2008 11:18:57 PM

My memory is using 1.8537volts
a b } Memory
November 20, 2008 11:27:36 PM

Some mb chipsets do this . With 4 sticks they run slower .

Its very unlikely to impact much on performance and I wouldnt worry about it
November 21, 2008 4:24:58 AM

Several memory sticks run @ 2.1 to 2.3 volts. What is the part # for the memory that you have? The memory I had a problem with ran OK with one stick too, but slowed when the second is inserted. If there are no bios settings for the memory, then you may be stuck with the slower speed.
Are the 4 RAM modules the same manufacturer and type?
a b } Memory
November 22, 2008 12:13:25 AM

OK great, you have told us that your computer is a Dell. Thanks for that. After all, Dell has only made one computer for the past 20 years, right? Same damned computer from 1988, just with some exterior styling differences.