Q9400 1333Mhz with 1600Mhz Mobo and 1066Mhz RAM


I got a little lost reading the overclocking articles as non of the users seems to have this combination.
I have a p5QL pro Motherboard with support for 1600Mhz system frekvencies, 1066Mhz RAM with cooling and a q9400 2,66Ghz 1333Mhz CPU.

1.) If I understand correct, the RAM devider is /2, so in my case 1066Mhz / 2 = 533 Mhz, my CPU has a devider of 4 as it is quad, so its @ stock 8 x 333Mhz.
I need to get it to 3.0Ghz or 3.2Ghz with a 1:1 ratio with CPU and RAM. The multiplayer for q9400 is locked (is it?) so I need to play with FSB

However I calculate I can´t get a this ratio:

If I put the CPU to 8 x 400 for CPU its 3200 Mhz but 800Mhz for RAM
If I look on the RAM = 533 x 2 = 1066 with a ration on CPU, it is 6 x 533 = 3,2Ghz, but 533 x 4= 2132Mhz for system Hz, which I have 1600 on my Mobo.
Can I get only to 400 FSB on CPU resulting 400 x 2 = 800Mhz on the RAM....or after the CPU OC, should I raise the RAM Mhz to 1066????

Am I getting something wrong?

2.) Also, I have a Ati Radeon 5870 GPU, I know that people are also leveling up the PCIe FSB to 100Mhz?? Does it go up automaticaly while OCing other components and/or do I need to change it to 100Mhz?

3 answers Last reply
More about q9400 1333mhz 1600mhz mobo 1066mhz
  1. FSB Freq = 333 MHz.
    Mem clock for 1:1 ratio is 667 MHz. (333 X 2)
    FSB clock = 1333 MHz (333 X 4)
    Core speed = 2.66 GHz (333 MHz X 8)

    Change your memory clock multiplier (or whatever it is called) from AUTO to 2.00. Now when you change the FSB freq, mem clock will double. If you can reach 400 MHz, your core freq will be 3.2 GHz.

    And if you are running the stock cooler, you will need better cooling.
    Here are two under $50 heatsinks that are pretty popular:
    http://www.newegg.com/Product/Prod [...] 6835207004
    Xigmatec Dark Knight
    http://www.newegg.com/Product/Prod [...] 6835233029

    They both require a somewhat different approach to applying thermal compound.
    Suggestions for applying thermal compound:
    http://benchmarkreviews.com/index. [...] mitstart=5

    And they are pretty large, so they might not fit inside your case.

    For a thread about overclocking RAM - or rather, why not to :

    I would also not recommend doing anything to the PCI-e socket. Left on AUTO, it will already be running at 100 MHz. Increasing PCI-e frequency can break expensive parts.
  2. To run 1066 RAM at full speed with a 400Mhz FSB you need to adjust the memory multiplier (probably manually).

    If you can't get the RAM to full speed, not all is lost, 1066 RAM often runs at 800Mhz with lower CAS timings. It varies between chips. My DDR2-1066 Corsair memory does 5-5-5-15, but at 920Mhz it is happy at 5-4-4-12. These lower latency timings have a big impact on memory performance too.

    I cheated and just run a 533Mhz (equiv 2132FSB) FSB, but that might not be possible (easily) with a quad core chip (so I'm told). I had to install a NB cooler as well, and I don't recommend these after installing one. Pain in the ass. But I'm doing my 533FSB on a Gigabyte board that is equivelent to your Asus.

    Also all Intel Core2 Quad, Duo, Pentium 4 chips etc have a quad line data bus. It's divided by 4 because its 4 lines, not because it's a quad core. It has 4 lines running at 333Mhz which is equivilent to a single 1333Mhz line (apparently, its marketing hyper really). My dual core was labelled 1333FSB as well.

    And when the motherboard makers say 'Supports FSB1600' it means that if an Intel CPU is installed, which requests FSB1600, it'll run at that speed automatically without any changes (except maybe a BIOS update) - it doesn't mean the board can't do more than FSB1600 :) It may need tweaks past this point but it'll do it.
  3. <my CPU has a devider of 4 as it is quad>

    (The divider is 4 for dual core processors as well.)

    I have a Q9400 myself, on a Gigabyte motherboard. I run my CPU at 3.4GHz, with the motherboard FSB set to 425MHz. I ran it for awhile at almost 3.8GHz, FSB at 470MHz, and it seemed to run fine there too but I didn't do extensive stress testing.
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