ASUS P7P55D Only Accepts One Chip from a 2-Chips Kit

[jaykchan]

My motherboard only accepts one chip of a G.Skill memory 2-chips kit.

I have a computer with the following components:
Motherboard: ASUS P7P55D
CPU: Intel i5 LGA1156 2.66GHz
RAM: G.Skill F3-12800CL9D-4GBNQ

The memory is a 2-chips kit with 2GB in each chip (4GB total). It is a DDR3-1600 at 1.5v. Somehow when I add either one onto the motherboard, the computer works fine. But if I add both chips onto the motherboard in dual-channels configuration, the computer "seemingly" works but will fail at some point.

The failures are like this: When I run a video encoding program for more than 30 minutes, the computer screen will go blank and cannot respond to Ctrl-Alt-Del and I must cold-boot it. When I used another computer to watch a MPG file stored in that computer, that computer screen went dark like what is described above and had to be cold boot. When I run Prime95 for 2 hours without any problem and then try to stop Prime95, the computer will freeze and screen image is not changed. When I run Memtest86, the computer screen will go blank (like what is described above) as soon as Memtest86 is only 45% done with the test#1; this happens very consistently. Seem like a memory-related problem to me.

Memtest86 works fine consistently after I remove one of the memory chip. When I replace the "good" one with the one I have taken out, Memtest86 continues working fine. This means there is nothing wrong with the individual chips. The motherboard doesn't seem like the presence of "two" chips.

Because of the fact that the CPU runs at 2.66 GHz but the memory is DDR3-1600, the manual of the motherboard suggests me to overclock the memory to 1600 to match the actual speed of the memory chip. Unfortunately, this doesn't help.

Please note that G.Skill F3-12800CL9D-4GBNQ is not in the list of the qualified memory chip according to the manual of the motherboard. This may be where the problem is. Unfortunately for me, I discover the problem after 30 days of my purchase and is not qualified for refund or replacement. I am stuck with this set of chips

My questions are:

1. Is there a way to make the motherboard to accept these 2 chips?

2. Can I put the chips in a different motherboard if I cannot make this ASUS motherboard to accept the chips? I assume I should avoid motherboard that runs at 2.66 GHz. Which speed of motherboard/CPU should I look for to match this set of chips?

Thanks for any info in advance.

Jay Chan

[jaykchan]

Tried XMP Profile But Doesn't Work

I come across a message in this forum about a similar error. That message is called "Computer Freeze - F3-16000CL9D-4GBRH". It suggested changing the memory profile to XMP and timing to 9-9-9-27. Unfortunately, this doesn't work for me. I changed the profile to XMP and the timing is automatically assigned as 9-9-9-24-2N-1-1.50V (cannot find a way to match the timing to what is suggested in the message). But the computer still has the same problem.

Any idea?

Thanks.

Jay Chan

[Tradesman]

I'd try disabling the XMP, set your base timings manually 9-9-9-24, DRAM Voltage to 1.5, want Command rate/Timing at either 2T or 2N, also check your tRFC if shown in NS (Nano Seconds) should be either 110 or 127 for 2 sticks, or if in clicks at about 66-68. Might also want to raise your vCore a bit

[jaykchan]

I have just tried almost everything that you have suggested. The situation seems to be a little bit better. Before the change, the computer would freeze at Memtest86. Now at least the system can reboot by itself after the failure in Memtest86. I have gradually increased CPU Core Voltage (vCore) from 1.168v to 1.1875v. But the system still fails Memtest86.

The only of your suggestion that I haven't tried is "if in clicks at about 66-68" because I don't understand what this means.

Any idea? Thanks.

Jay Chan

[jaykchan]

Problem Solved

I finally fix the problem. Seem like the problem is as simple as the memory testing program (MemTest86 version 3.5) doesn't work in my configuration. The problem doesn't show up when I switch to the older version of MemTest86 (version 3.4). I have also tried 2 other memory testing programs (MemTest86+ 4.00 and M2K MemScope version 1.10. Both test the system OK.

With the memory set at 1600 using the D.O.C.P setting of the ASUS BIOS, the system works fine. But this requires the CPU to be slightly overclocked with a 17 multiplier to something like 2.75GHz instead of the stock 2.66GHz. I don't really want to overclock this system because I want it to be very stable and give me the least headache. Therefore, I set the DRAM frequency to 1333MHz to avoid any overclocking. I should have bought the DDR3-1333 version of the G.Skill memory chip to avoid all this trouble. But when I ordered the memory from newegg.com, I didn't realize that I will need to overclock the system to use the DDR3-1600 chip because the spec in newegg.com states that 1600 is "stock", not "OC".

Now that the memory is set at 1333MHz, I can run all those memory testing programs (except for MemTest86 version 3.5) without any problem. And I have encoded a 30 minutes video without any problem. I can also stop Prime95 after 10 passes of test without any problem (this is the first). And this doesn't affect the Windows Experience Index either.

I am glad that this is over.

Jay Chan

[Tradesman]

Sounds good....don't be afraid to OC, you won't really lose any stability, Intel always underrates their CPUs, if it's rated 2.66, it should easily be good through 3.0, on air, with the stock heatsink