I have a new motherboard Asus p8z68v--LE and the RAM led is blinking have already tried only ram stick in all four slots and it doesn't get past POST still and I known it isn't the motherboard as everything else is turning on andn working properly.Therefore I would like to known if using memtest x86 without POST is a good idea for testing for bad memory.
try getting a different ram stick from the ones you have, maybe borrow a friends for a few mins to see if its your ram thats flawed or the new MB. If this is the ram you had working before and you just got a new MB most likely it is the MB that is flawed but just to make sure test the MB with different ram sticks. Maybe you damaged your ram in the process of switching motherboards.
nekulturny is CORRECT the problem could be Ram or MB. Have to add the CPU to the mix as memory controller is on-die for SB CPUs. Also just to reiderate - No you can not run Memtest86, not boot to anything from a DVD without first getting past the post.
.. memory controller problem could be MB or CPU as memory controller is inside CPU.
.. Has voltage regulator to convert +12 V to your Ram voltage of 1.5V
.. Also problem with one of the contacts.
Ram, Yes Higher probability.
.. Not compatable.
.. Defective ram
...... If Both sticks are defective. It is possible that you damaged them due to improper handling - ESD. While manuf do turn out some defective sticks, ESD damage by the user is probably higher. Your body typically has 30->100 volts of static build-up and you will NEVER know it. HUM, Ram operates @ 1.5 V and you supply 30->100 volts by touching a pin. NOTE: Not saying this is what Happend, and you does not refer to You, but is used collectively.
..Also make sure the stick is FULLY seated and side clips locked - I've had problems with this.
Sorry, But the ONLY way to definatively state the ram is defective and MB is NOT the problem is if You try a (A) listed as compatable and (B) Ram stick is KNOWN to be good.
Couple of side points:
.. Your DDR3-1600 will run at 1333 UNTIL you change it in BIOS (which at the Moment you can not get to).
.. DDR3-1600 may void your CPU warrentee (For SB CPUs). Intel specs are for Ram are (A) max Vdimm of 1.575 V and 1333 speed)
.. Very little, if any real life advantage in DDR3-1600 vs DDR3-1333