Mem86 error / advanced memory timings

[Stranger2000]

Hello,

 

My motherboard is a brand-new Intel DX38BT with an Intel Core 2 Quad 2.8 GHz CPU.

 

Initially, I had four CM3X1024-1333C9 that came in two packs of two. One pack came with the motherboard, and I purchased another separately. At the motherboard-detected settings of 1066 MHz, 7-7-7-20, 1.53V, everything seemed to work. Changing the settings to what the memory is supposed to be -- 9-9-9-24, 1.7V, 1333 MHz created weird instability problems, like Windows not being able to find tcpip.sys on bootup, random crashes, etc. Running memtestX86, I got an error within the first megabyte on the second pass of the test.

 

I read in the Corsair FAQ that memory sets purchased separately might have problems, so we submitted the four DIMMs for warranty replacement and received part number TW3X4G1333C9DHX -- two matched DIMMs of 2048MB each. Again I set the correct voltage and timings, and ran memtest -- getting the same error, also in the first megabyte, as before, on the first pass. I also noticed that my memory bandwidth, as reported by MEMTEST, seemed kind of low -- 4818MB/sec.

 

I noticed that in addition to the usual timings and voltage setting, my BIOS has advanced memory timing parameters - tRFC, tRRD, tWR, tWTR, tRTP. By default these were 60,4,8,4,4. I read that someone had problems similar to mine, but solved them by increasing the last four of these by 1. I tried that, ran MEMTEST, and got the error you see in the attached file. Again an error in the 1st megabyte. Unsurprisingly, the bandwidth was now even lower -- 4.6 GB/sec.

 

I could really use some help!!!

[DerekT]

When you populate all four DRAM slots, it is advised to drop the DRAM speed one bin. So 1333Mhz DRAM in a two slot (1 Kit) population would do well to be dropped to a 1066Mhz DRAM speed in a four DRAM slot population.

 

Please research this thread:

 

http://www.houseofhelp.com/v3/showthread.php?t=64360&highlight=Unpredictable+results+QUAD2X4096+Gigabyte+X38-DS5

 

Use Memtest86+ version 2.01 from http://www.memtest.org

[Stranger2000]

Derek,

 

Thanks for your suggestion. Currently I only have two slots populated, one on each channel, since Corsair sent me a replacement kit of 2 2GB DIMMs. I am still getting a memtest error at 1333, which disappears at 1066. Curious that the motherboard detects these chips as 1066, but they're sold as 1333 and I don't think it's unreasonable to expect them to work at that speed. I am really hoping to hear back from Corsair about this!

[DerekT]

Derek,

 

Thanks for your suggestion. Currently I only have two slots populated, one on each channel, since Corsair sent me a replacement kit of 2 2GB DIMMs. I am still getting a memtest error at 1333, which disappears at 1066. Curious that the motherboard detects these chips as 1066, but they're sold as 1333 and I don't think it's unreasonable to expect them to work at that speed. I am really hoping to hear back from Corsair about this!

 

Download CPU-z from

Here

.

Please post a screenshot of your CPU/Memory and SPD tabs. You will note in the avanced timings table settings that show the advanced timings and speeds. These should show the 667Mhz (1333Mhz at DDR) speeds.

 

Edit:

 

By the way, Corsair will respond here. If you post my request, you will help them answer you more quickly though.

[Stranger2000]

The CPU-Z screenshots are attached.

Running CPU-Z now I noticed that the two 2GB modules they sent have different advanced timings than the 4GB modules. Those are pretty long latencies! I'll have to try them, though.

[RAM GUY]

With 4 modules DDR1066 would be suggested and If Command Rate is listed it will need to be set to 2T with more than two modules installed.

[DerekT]

Set to 9-9-9-24 and 2T and retest. Since you are populating with 2 DRAM slots, you can set to 1333.

[Stranger2000]

Derek,

 

Thanks for following up. I'm going to try the advanced timings from CPU-Z over the next couple of days. By the way, what is 2T?

 

Thanks!

[DerekT]

By the way, what is 2T?

 

2T is a DRAM command rate and is referenced to the memory controller. The Memory Controller needs to access your memory. It connects to a memory bank to do this selection. After the memory controller connects to the memory bank, it moves to select the column of the DRAM. Once it has found the column of memory it moves to access the row, find the data repository, and either store the data in the repository, or return the data from the repository to the controller, and on to the CPU. This is how data in the DRAM is accessed and stored by the memory controller. Think of the DRAM as a giant Rubiks cube with each line a column and each single block a row. It's not exactly like this but the comparison helps to visualize the storage, movement and transferal.

 

1T/1N is the time it takes 1 clock tick/cycle to connect to the bank of memory bank. 2T/2N takes 2 clock ticks/cycles to connect to the bank of memory. This only occurs at the first access of the bank and all accesses of that bank after the initial access are performed immediately without delay of any ticks.