AMD2+ Compatibility Confusions

Phenom I cpus will definately work such as this one: http://www.amazon.com/AMD-HD9550WCGHBOX-Quad-Core-2-20G....
This phenom II may also run, but require a bios flash which involves some risk to the motherboard: http://www.amazon.co.uk/AMD-Phenom-Cache-Quad-Processor....
I would try hp's online tech support for advice: here's a link: http://h30434.www3.hp.com/psg/. Good luck.

Well from what I can tell reading the information provided by HP as long as the CPU is 95W and of the AM+2 socket you should be fine to upgrade. This would mean as an example the AMD Phenom II X4 850 should work because AM3 CPU's will work in AM+2 boards.

Read over this forum.

http://www.tomshardware.com/forum/264935-28-best-proces...

Usually you have to upgrade your BIOS in order to use newer CPU's compatible with your mobo.

BUT, your mobo doesn't appear on Asus official page, and is there where you can find wich processor your mobo can use and which BIOS version is required.

If I'm not mistaken Athlon X2 7850 should be one of your best options

Here you have all AMD CPU's that are AMD2+ and have 95 watt

http://products.amd.com/en-us/desktopcpuresult.aspx?f1=...

BUT !!! Remind to check wich BIOS you need to swap your CPU

You have an hp board, even though it's made by asus, so it has an hp bios. Check with hp for bios updates and read the instructions carefully before flashing. Lots of folks, including myself, have had bad flashes. When this happens, the board is toast unless you can find a used or bad hp board just like yours. Then you can replace the bios chip, but hp doesn't stock them. So proceed with caution.

I don't think we want to even risk fooling with a BIOS flash, so I guess I'm just looking for best options on that current BIOS and that current motherboard revision.

I would still try contacting hp tech support. They used to have a "live chat" option but I don't find it anymore. I would specifically ask about the 95w 945 phenom II I listed above. Maybe they can answer your question about this cpu; it's the best that may work without a bios flash, but only they would know. The odds of finding someone who's tried it are pretty low, but again, using the hp forum is free and you might get lucky.

" I'm also confused by the fact that, according to that chart, apparently many quad cores are weaker than his current dual core variation?"
Just a note about this:
It will not happen except in some "pure gaming" cases.
In other words it may look like that only in some test conditions / and in DOS mode  /.
Almost nowhere in the real world, except if you compare a really fast dualcore with a really slow quad ofcourse. Not in a case you game when a browser is opened in background with some content opened /in tabs/ and some flash is there in and especially if the browser is Chrome /a well multithreaded one/, a resident disk optimization or network monitoring program suddenly kicks for CPU, an antivirus is permanently on, the OS itself has like tens of resident processes with like hundreds of threads and this is just the basics...
IMHO a quad-CPU system is more stutter proof in gaming /in "real world"/.
Quad is definitely better in everything utilizing some kind of "rendering" /like video processing or 3d/, pixel crunching /well, rendering is a case of that too/, data chewing, engineering or scientific calculations etc. etc.
The proved efficiency of Intel's HT in quadcores when they double the simultaneously executable threads from 4 to 8 without even adding real execution units and probably only lowering the stack operations should speak here for itself.
/Well, a point of note here may be the question like why then a 8-way BD is in many cases worst than a 6 core Phenom, but the thing is, a 8-way BD has only 4 FP units while 6-Phenom - 6/