Laptop does not recognize first RAM after install of second RAM

jon905

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Dec 31, 2011
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Hi,

I have an old HP Compaq 8510w notebook, which came with 2GB RAM. According to the specs, this machine supports up to 8 GBs (http://h18000.www1.hp.com/products/quickspecs/12727_na/12727_na.PDF). The originally installed RAM has part number HYMP325S64AMP8-Y5. It is DDR2 at 667 MHz (see here, e.g., for specs: http://www.memory4less.com/m4l_itemdetail.aspx?itemid=1442559183&partno=HYMP325S64AMP8-Y5%20AB-A).

My other laptop recently died and has 2 1GB RAM sticks that are also DDR2 at 667 MHz. They each have part number hys64t128021hdl-3s-b (see here, e.g., for specs which match the original RAM stick except in memory size: http://www.memory4less.com/m4l_itemdetail.aspx?itemId=249590158&rid=fd_13_2_16_594&gclid=CP_J3MuyrK0CFaIRNAodf2XDlg).

When I put one of these 1GB sticks into the laptop, only the new one is recognized and not the old one. I checked the OS, BIOS, and CPU-Z. I switched around memory slots and tried both 1 GB RAM sticks, but still I only have the computer recognizing 1 GB RAM.

Can anyone help me resolve this, or is there is something incompatible that I just do not realize?

Thanks,
Jon
 

jon905

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Dec 31, 2011
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The notebook does recognize both 1 GB modules when they are installed. The 1GB + 2GB might not be compatible as you said. Is there somewhere I could find that type of information?
 

jon905

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Dec 31, 2011
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I did some more investigating, and I did find a spec for the computer that said it only supports dual channel symmetric memory. So I guess you are correct. Thanks for the help.
 

I asked because the table in the PDF document only included single channel memory or dual symmetric memory; no other combinations were suggested.