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My system uses an Intel D975XBX2 motherboard with the final 2838 BIOS and an Intel E6600 CPU (2.4GHz stock with a locked 9x FSB multiplier). I have run the CPU at 3.0GHz in the past with no problems and would like to continue to do so.
Since I bought the system 3 years ago, I have been using 2x1GB of Crucial Ballistix DDR2-1000 BL2KIT12864AA1005. After asking around, I got this suggestion for my RAM setttings:
Therefore, I set the FSB to 333MHz, the Reference Frequency to 266MHz, the Memory Frequency to 800MHz, the timings to 5-5-5-15 and the memory voltage to the required 2.2V. This has worked great for 3 years and still shows no errors in a 10-hour run of Memtest86+ 4.00.
I upgraded to Windows 7 64-bit, and decided it was now or never for upgrading the amount of RAM. Finding a similar set of 2.2V DDR2-1000 RAM seems impossible, so I went with the 2x2GB GSkill 1.8-1.9V DDR2-800 F2-6400CL5D-4GBPQ.
I didn't really expect that the two kits would co-exist peacefully but I tried anyway. I left the Crucial RAM in the first pair of dual channel slots, put the GSkill RAM in the second pair, and left the BIOS settings alone; Memtest86+ immediately and constantly threw errors. I was not able to find any setting that did not cause the same errors, even with the CPU set to stock speed and RAM reference and memory frequencies set to default.
So I took out the old Crucial RAM and have the new GSkill RAM running by itself in the first pair of slots. With the FSB at stock speed of 266MHz (putting the CPU at stock speed of 2.4GHz), the RAM reference and memory frequencies set to default and the memory voltage at 1.84V, it passed one Memtest run. I then increased the FSB to 333MHz, and Memtest86+ started showing errors partway through the first run at test #6. 1.88V did the same thing (errors at test #6) but 1.92V has now passed two runs with no errors.
Out of curiosity, I then increased the voltage to 2.2V and the GSkill set did not immediately throw errors like it did before when I attempted to run both sets of RAM. So I tried putting the Crucial set into the second pair of slots and trying a variety of voltages, but that once again always resulted in immediate errors, so I took the Crucial set out again. The two sets can run stable at the same settings, just not together. Any insights as to why that is?
So here are my current settings with the GSkill set:
CPU 3.0GHz
FSB 333MHz
Reference Frequency 266MHz
Memory Frequency 800MHz
tCL 5
tRCD 5
tRP 5
tRASmin 15
Memory Voltage 1.92
Memtest86+ shows these settings to be "RAM: 500 Mhz (DDR1000) / CAS : 5-5-5-15 / Dual Channel (Interleaved)"
I'll be running Memtest86+ 4.00 on those settings overnight. Are there any settings that might be better than this?
There is a D975XBX2 memory calculator to better understand how its reference and memory frequencies work (a concept which I still fail to entirely grasp).
Since I bought the system 3 years ago, I have been using 2x1GB of Crucial Ballistix DDR2-1000 BL2KIT12864AA1005. After asking around, I got this suggestion for my RAM setttings:
If you only want to push to 3ghz, you wont be able to overclock your ram. The reason is that 3000mhz = 333mhz (fsb) x 9 (default multi). The highest divider available would be 266mhz ref frequency - 800mhz mem frequency = 2:3 divider = 333fsb/500mhz ram --> DDR2 ---> 1000mhz ram which is the default timing for your ram.
I upgraded to Windows 7 64-bit, and decided it was now or never for upgrading the amount of RAM. Finding a similar set of 2.2V DDR2-1000 RAM seems impossible, so I went with the 2x2GB GSkill 1.8-1.9V DDR2-800 F2-6400CL5D-4GBPQ.
I didn't really expect that the two kits would co-exist peacefully but I tried anyway. I left the Crucial RAM in the first pair of dual channel slots, put the GSkill RAM in the second pair, and left the BIOS settings alone; Memtest86+ immediately and constantly threw errors. I was not able to find any setting that did not cause the same errors, even with the CPU set to stock speed and RAM reference and memory frequencies set to default.
So I took out the old Crucial RAM and have the new GSkill RAM running by itself in the first pair of slots. With the FSB at stock speed of 266MHz (putting the CPU at stock speed of 2.4GHz), the RAM reference and memory frequencies set to default and the memory voltage at 1.84V, it passed one Memtest run. I then increased the FSB to 333MHz, and Memtest86+ started showing errors partway through the first run at test #6. 1.88V did the same thing (errors at test #6) but 1.92V has now passed two runs with no errors.
Out of curiosity, I then increased the voltage to 2.2V and the GSkill set did not immediately throw errors like it did before when I attempted to run both sets of RAM. So I tried putting the Crucial set into the second pair of slots and trying a variety of voltages, but that once again always resulted in immediate errors, so I took the Crucial set out again. The two sets can run stable at the same settings, just not together. Any insights as to why that is?
So here are my current settings with the GSkill set:
CPU 3.0GHz
FSB 333MHz
Reference Frequency 266MHz
Memory Frequency 800MHz
tCL 5
tRCD 5
tRP 5
tRASmin 15
Memory Voltage 1.92
Memtest86+ shows these settings to be "RAM: 500 Mhz (DDR1000) / CAS : 5-5-5-15 / Dual Channel (Interleaved)"
I'll be running Memtest86+ 4.00 on those settings overnight. Are there any settings that might be better than this?
There is a D975XBX2 memory calculator to better understand how its reference and memory frequencies work (a concept which I still fail to entirely grasp).
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