I've had mixed results when mixing memory from different brands.
If the mb only supports up to pc2100, the pc2700 will simply run
at the slower speed.  The CL 2.5 (cas latency) is also a speed
rating, 3.0 is slower than 2.5 or 2.0.  If the Kingmax is rated at
3.0, your infineon will also slow to the CL of 3.0.  I've had 2
different centon chips that worked fine (in different computers)
for a few months, then started causing errors until removed.
My personal preference: try to match the infineon chip, or put in
  one 512 chip or 2 matching 256 chips.

Tal Wolfe wrote:

> I just purchased a used Compaq Presario 2596US laptop and I want to add another 256MB of memory. Currently it has the following RAM:
> Infineon
> HYS64D32020GDL-6-B
> 32M x 64 SDRAM
> PC2700S-2533-0-A1
> 256MB, DDR, 333, CL2.5
>
> All the memory configurator's tell me that this laptop should have DDR 266 PC2100 in it. I would like to use one of choices if possible:
>
> Kingmax 256MB 200-Pin DDR SO-DIMM DDR 333 (PC2700) Notebook Memory Module MSAB62D - OEM
>
> or
>
> Kingmax 256MB 200-Pin DDR SO-DIMM DDR 266 (PC2100) Notebook Memory Module MSDB62D - OEM
>
> These are available from newegg.com for under $21.00 (great price!)
>
> WHICH ONE SHOULD I USE? THANKS!!!
>
>          PCBUILD maintains hundreds of useful files for download
>                      visit our download web page at:
>                   http://freepctech.com/downloads.shtml

            Do you want to signoff PCBUILD or just change to
                    Digest mode - visit our web site:
                   http://freepctech.com/pcbuild.shtml