Can only use 2 sticks of RAM rather than 4?

[krisdeancooper]

A while back I bought a new computer. The motherboard I bought was an ASUS P7H55-M PRO/USB3 and I have an i3-550 with 4gb of XMS3 Classic Ram (2 x 2gb sticks, 1600mhz). When I bought the computer I set it up with the stock intel cooler and put the two sticks in dual channel slots which worked a treat. After I tried overclocking my CPU was gettin really hot and I decided to fork out for CM 212+ Hyper cooler. When I installed the cooler I noticed that my computer wouldn't boot and eventually found RAM was the problem. When I put the two sticks in single channel, next to each other, the computer booted fine.

Fast forward a year and I bought another 4gb to go along with my GTX 670 to give my gaming a little extra oomph. The RAM is the same brand and timings but when I put the four sticks in I have the same problem as I have when I put two in dual channel, which is no boot.

If it's important, my PSU is an OCZ ModXStream 600w modular. Please help me, this is doing my head in!!!

 

[o1die]

A ram stick may not be seated, or one is bad; test each one at a time with memtest. The problem started with the hyper 212, so you may want to reinstall it. Sometimes too much force is exerted around the socket area with any cooler; don't know if this effected the ram; you'll just have to test them. I use an esd strap when handling components several times; use one if you have it.

 

[krisdeancooper]

I tested all the sticks already and they all work. The problem seems to be two of the ports but i was just wondering whether anybody knew why they suddenly stopped working or at least had an idea. I'll try re-seating the cooler. I'll update with my progress.

 

[krisdeancooper]

I tried taking the cooler off altogether and it didn't work, tried reseating it and the ports still don't work. Anyone got any ideas? This used to work fine but it's just making me mad now.

 

[AntiZig]

you said that the dual channel didn't work from the start, I think you might have a defective ram slot

 

[krisdeancooper]

The Dual Channel did work initially. It was since I got the Cooler.