|"I read somewhere that my motherboard didn't support my x6 out of the box, could this be the problem?"|
Yes, if the present bios version the mboard has is not high enough.
The probable (unofficial) cpus supported by your mboard model:
Asus also has an official CPU support list, but this one shows the cpu model numbers at the left.
According to that, the bios version for the X6 ones must be at least 2002 or 2005 depending on which one.
There is usually no way of determining what present bios version the mboard has if the mboard won't boot, but you could try emailing Asus and include the model and serial number for the mboard.
You could look on the label on the box the mboard came in, or on a label on the bios chip if there is one, but I've never seen the bios version on that for an Asus mboard, or any mboard.
If there is a date on the label on the box the mboard came in that states when it was made, you could look at the list of bios updates on the Asus site to see which bios updates it could have been, and can't have been, flashed with. If a date of a bios update is close to and a little older than the date the mboard was made, it may have been flashed with the update previous to that, rather than that one.
When you bought the mboard doesn't necssarily help determine which bios version the mboard has, other than it can't be newer than when you bought it - it may have been sitting on a shelf for a while.
You could take the system to a computer builder's place, have them install a cpu on it that works with any bios version - if the mboard boots fine with that, they could flash the bios with the latest non-beta version. Then your X6 cpu should be recognized by the mboard fine, if it's one of the ones listed.
You may have installed incompatible ram - ram that can't work in this mboard - or have installed it in the wrong slots. That alone can cause no boot, no beeps.
Quote the make of and the part numbers on the ram you are using.
It is easy to test for incompatible ram that has caused your mboard to fail to boot.
Make sure you have a speaker or speakers or the equivalent connected to the mboard so you can hear mboard beeps (see your mboard manual if you need to).
Remove the AC power to the case/power supply.
Remove all the ram.
Restore AC power.
Try to boot.
If nothing else is wrong, you will get no video but you will hear a pattern of beeps that indicate no ram is installed, or a ram problem.
E.g. for an Award bios or a bios based on one, that's often a beep of about a half second, silence for a half second, a beep of about a half second, silence for a half second, continuously.