imac 27" a1213 - data integrity check

Hi guys.

I've been trying to fix a iMac that makes me crazy.

Normal boot: apple logo and then white screen.

Holding alt: choosing recovery partition: apple logo and then white screen.

Putting a Leopard OSX boot cd in and booting from that: 3 beeps 5 sec pause 3 beeps and so on.

Reseating RAM - apple logo and white screen.

Checking one ram at a time - sometimes it beeps 3 times just after i turn on, other times it does the white screen

I've checked with another RAM from a lenovo computer - the same, either white screen or the three beeps and 5 sec and so on.

I've done heaps of PRAM(NVRAM) resets.

It can boot single user mode, but NOT hardware test.

The RAM in it right now is 4x4gb:

cms04gx3m1a1333c9 corsair value select

It has been upgraded ^

I'm not sure to tell the customer to buy new memory, as I really don't know if thats the faulty hardware, since it does the same on my lenovo ram.

have you got any idea?

Cheers, Rasmus