Problem with memory upgrade in hp dc7900 sff

[thefixer713]

I am attempting to upgrade the PC2-6400 DDR2 memory in my dc7900sff. I currently have 4x1gbs installed. The specs state that I can upgrade to 16gbs (4x4gbs) but after I do the swap and try to restart the pc it will not start. Does anyone know what I might have missed?
In case it's important, I have upgraded to a core2Quad processor and run windows7 x64.

 

[algorithmbreaker]

I am attempting to upgrade the PC2-6400 DDR2 memory in my dc7900sff. I currently have 4x1gbs installed. The specs state that I can upgrade to 16gbs (4x4gbs) but after I do the swap and try to restart the pc it will not start. Does anyone know what I might have missed?
In case it's important, I have upgraded to a core2Quad processor and run windows7 x64.

Install one 4 GB individually to see if any of the RAM is defective. 4 x 4 GB is supported by your HP Compaq dc7900 Small Form Factor system.
Links you might want to refer
https://h20565.www2.hp.com/hpsc/doc/public/display?sp4ts.oid=3785403&docId=emr_na-c01637675&docLocale=en_US
https://h20565.www2.hp.com/hpsc/doc/public/display?sp4ts.oid=3785403&docId=emr_na-c01869333&docLocale=en_US

 

[thefixer713]

One of the links you suggested said:
In addition, the computer supports the following:


•512-Mbit and 1-Gbit non-ECC memory technologies.


•Single-sided and double-sided DIMMs.


• DIMMs constructed with x8 and x16 DDR devices; DIMMs constructed with x4 SDRAM are not supported.

The modules I have say:
4gb 2Rx4 PC2-5300P-555
Is it the x4 indication that could be the problem?

 

[algorithmbreaker]

One of the links you suggested said:
In addition, the computer supports the following:


•512-Mbit and 1-Gbit non-ECC memory technologies.


•Single-sided and double-sided DIMMs.


• DIMMs constructed with x8 and x16 DDR devices; DIMMs constructed with x4 SDRAM are not supported.

The modules I have say:
4gb 2Rx4 PC2-5300P-555
Is it the x4 indication that could be the problem?

Yes, it could be. because this system does not support the x4 Chips

 

[thefixer713]

Thanks for your help. It seems to me that there should be an industry standard. It would make upgrades so much easier.