thank you for taking the time and responding to my post.
the computer doesnt beep when i turn it on, the screen is just black. the ram is non-ecc for desktops. what does reseating the graphics card have to do with installing the ram? that just seem to come out of no where. but, you have the experience to know that it might.
all the ram is matching and meets the specs posted on the hp website for memory upgrade of this mobo model.
when i ran the crucial memory upgrade device on my computer it only gave me options of memory upgrades for up to 8gb of ram. why is that?
also, i read on one of the forums here that the board actually doesnt take 16gb of ram only 8gb. to get 16gb to work you need the H version of this board not the N version. everywhere else on the web i see that the specs say it can take 16gb of ram.
do i need to change the power supply and add power to the 4pin plug next to the main mobo power supply to get the board to read the 16gb of ram?
thank you for taking the time to respond to my post. i've read all the info and followed the specs on the site. i've installed the ram from 2 different manufactures and end up with a black screen when i turn on the power.
the crucial website tool scans my system and only gives me options of upgrading my system to 8gb ram max. why is that?
also, i've read on this site in another forum that the N version of this board only supports 8gb of ram max and the H version is the one that supports 16gb.
is there a setting on this board i need to adjust to get it to work with 16gb of ram or do i need to add power via the 4 pin plug next to the main mobo power harness to get it to read the ram?
To perform additional checks you should try returning to the original memory configuration and verify that everything works, and also trying to boot with just one of the new DIMMs inserted (nothing else) and possibly various other trial combinations of DIMMs to try establish more about the problem. (if you have not already done this)
RAM problems (eg wrong type) are often indicated by the computer beeping on boot. In fact the number and and pattern of the beeps can tell wich area the fault is in, for example on some wotherboards a RAM problem will be indicated by a single beep, repeated on others this may indicate another type of problem. What the beeps mean will be described in the m/b manual, or maybe other places. But your computer doesn't beep.
About reseating the graphics card, I was just thinking of other reasons your screen might be black. You may have knocked something without noticing, in this vein also check the power cable to the graphics card if present. Do not assume I am an expert !!
(It would savea bit of effort if you could clarify unambiguously the model of your PC -is it a p6650z or a p6720f ?) The HP specs for the RAM in the p6270f (http://support.hp.com/us-en/document/c02628244 and the p6650z (http://support.hp.com/us-en/document/c02583832 are not very tight, and say/imply only that it should be PC3-1066 [1333 "MHz"]. Different manufacturers make RAM with slightly different timing reqiurements which may not work in your computer, though it meets the spec on the HP website. Often m/b manufacturers or PC sellers will have a qualified vendor list (QVL) where the acceptable manufacturers of the various components are listed. You might try checking this. The info given there for p6720f is that it supports 16GB RAM, as 4 x 4GB DIMMs with the N variant of the m/b. HP say about the p6650z that it has the H variant, but they do not give upgrade information, only that they will supply it with at most 4 x 2GB DIMMs of PC3-1066 and that it will support 16GB of RAM.
Crucial RAM (I used the memory advisor tool) give 16GB RAM for the p6720f and only 8GB of RAM for the p6650z [in contradiction the specs on the HP website](not to exceed manufacturer supported memory ??) and supply 4GB DIMMs and 8GB "kits" (2 x 4GB) with different p/ns for the two models (for p6650z see http://www.crucial.com/usa/en/compatible-memory-for/HP---Compaq/pavilion-p6650z and for the p6720f see http://www.crucial.com/usa/en/compatible-memory-for/HP---Compaq/pavilion-p6720f). Interesting Crucial say that PC3-12800 speed memory will work, and for the p/ns listed for each model they have tested them in the appropriate model and guarantee that they are compatible. Other p/ns forexample from their value RAM range which have the same nominal spec. may work in your computer but Crucial do not that they will and have not necessarily tested those p/ns to be compatible.
Presumably the crucial memory upgrade device on my computer only gave me options of memory upgrades for up to 8gb of ram because to upgrade to 16GB you would need to buy 2 lots of the 8GB upgrades. I am not ertain about whether Crucial's 2 x individual 4GB modules will support dual channel operation but the two modues in the 8GB kits are guaranteed to. Because of the way dual channel works, you only need pairs of identical modules put in the right slots, so there is no need to sell 4 x 4GB identical (matched) modules.
"also, i read on one of the forums here that the board actually doesnt take 16gb of ram only 8gb. to get 16gb to work you need the H version of this board not the N version. everywhere else on the web i see that the specs say it can take 16gb of ram." - see my remarks on the difference between the p6650z capabilities given on the HP website and the Crucial websites. You might try looking the up on the Foxconn site (though it may be a difference the BIOS chips on each m/b which I think is HP specific) and discussing the discrepancy with Crucial (HP support ae usual inaccessible if your computer is not the latest model)
"do i need to change the power supply and add power to the 4pin plug next to the main mobo power supply to get the board to read the 16gb of ram?" Maybe the extra memory is drawing more power more power than your PSU can supply but I think this unlikely (you can try the power requirements calculator with your computer details with both your our original RAM configuration an with the 16GB and look at the difference to get an idea - http://extreme.outervision.com/psucalculatorlite.jsp I think it is even more unlikely that you need more power through the 4 pin m/b connector.