Your RAM isn't on Asus' memory QVL (Qualified Vendors List)-but that isn't to say that it's not supported.
Having your power supply checked might be an option if your graphics card seems to run slow or you are getting fluctuating performance.
Because OCZ memory modules lack what are called embedded XMP profiles, your motherboard will have difficulty assigning a setting for them so you will need to do it manually.
Download Memtest86+ from here
http://www.memtest.org/#downiso
***under the Memtest86+ v4.00, select "Download -Pre-compiled bootable iso ", save and unzip if downloading the zip file then burn a BOOTABLE CD using ImgBurn or your usual burning software (Nero etc.).- this program runs at BIOS level
Download MemSet here
http://www.softpedia.com/get/System/System-Info/MemSet.shtml
You can also download CPU-Z -it gives a much simplified version of the RAM timings but you can also access chipset and CPU info. download here
http://www.cpuid.com/cpuz.php
First order of business would be ascertain whether the RAM modules are not defective.
I presume the RAM in question is OCZ's Gold XTC modules - if they are then you can try to manually select the timings- they should be on a sticker on the side of the RAM, which should be 7-7-7-21 ( CAS (or CL)-tRCD-tRP-tRAS) at 1.5 to 1.6 volts.
IF THIS IS NOT YOUR RAM THEN GO NO FURTHER, If it is then you need to set it in order to test it for stability.
Boot into your BIOS. Select the second tab "A.I.Tweaker"
Set PCIE Frequency to 100 (if not already set)
Set DRAM Frequency to DDR3-1066 (if not already set)
Set DRAM Command rate to 2T (if not already set)
Set DRAM Timing Control to Manual
Note the string of timings following "Pri.Information" on the next line-they should be the same as the settings you are about to input.
Set CAS# Frequency to 7 DRAM Clocks
Set RAS# to CAS# Delay to 7 DRAM Clocks
Set RAS# Precharge to 7 DRAM Clocks
Set RAS# Active time to 21 DRAM Clocks
leave the rest of the timings on Auto for now and move down the page until you get to..
DRAM Voltage ....type in 1.60
Hit F10 to save and exit
**If you can boot into windows then run Memset (NOT the Memtest86+ cd you burned!) and note -or better still get a screen capture of the timings (and include in your next post)-here is an example of one of my old screenshots-take no notice of the values but note that both modules SPD (A and B )values are shown-so expand the window.
** If you cannot load Windows then get back to the BIOS and revert settings by choosing Restore Defaults, F10 to save and exit. The likely cause will be insufficient MCH (Northbridge) voltage.
If Memset shows you the correct values and voltage then you can move on to testing.
Reboot and select CD as your first bootable drive
Insert your Memtest86+ bootable cd into the drive
Hit F10 to save and exit
Memtest86+ will boot automatically once the motherboard POST's. As it's a DOS program it is fairly straightforward -The test actually comprises 8 seperate tests. Once all 8 have run then your RAM has completed a "Pass" -for 4Gb a Pass takes around 20-30 minutes.
Run 7 (minimum) to 12 passes. If the testing shows no errors then stop the test at your leisure.
Return to your BIOS, change the boot order back to Harddrive (I assume)
Take the CD out of the drive
F10 to save and exit -congratulations your RAM is stable. The next step would be to stress test the CPU/RAM fo test for stability- but one thing at a time
If the test throws up errors then note the Number of the test and the error code- the test will continue if the errors are not to great. If the testing serquence stops then stop the test, reboot, change boot order, remove cd and F10.
The RAM could fail from either physical damage it has suffered or the timing (and sub-timings) are unstable. We can look into that if the need arises.