Hey guys and gals.

Heres my predicament.

Im pretty new to overclocking my system is

windows 7 32
P5W DH DELUXE motherboard
intel e8400 core 2 duo processor
Kingston HYPERX KHX8500D2K2/4G 4GB DDR2 1066MHz Non-ECC CL5 5-5-5-15 2.2-2.3V
ati 4870 gpu.

I can overclock my cpu to 3.6 g no probs without having to change anything else, but it seems like my ram is suffering. When i go into the bios my ram is set to 4-4-4-12. When i set it to 5-5-5-15 and restart my pc all i get is a black screen, so i set my cpu back to standard 333 and try my ram at 5-5-5-15 and the same happens again a black screen on start up.

Can anyone help me please.

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  1. Best answer
    Let me try to get this straight. You change the FSB from 333 to 400, leaving the CPU multiplier alone. This puts you at 3.6GHz, no clue on the ram speed. When you go into the bios, you see the ram is set to 4-4-4-12, and even though its working you set it to the slower 5-5-5-15 which cause a bad boot.

    If you put the FSB at 400, change the ram multiplier so that its running at 800MHz. First see if this works. If it does, try lowering the timings to 4-4-4-12. (if already at 4-4-4-12, leave it alone.) If that works, see if you can run it at 2.0, and then 1.9, and then 1.8v. I'm not sure you'll get there with that ram. Good OCing ram will do 1066MHz with CL5 timings with perhaps 1.8-2.0v. If yours needs that much voltage, I'm not sure how well it will handle CL4 at 1.8v, even if its at DDR2-800.
  2. Looking at Kingston Datasheet concerning those memory sticks:

    Each module pair has been tested to
    run at DDR2- 1066MHz at a latency timing of 5-5-5-15 at 2.2V. The SPD is programmed to JEDEC
    standard latency 800Mhz timing of 5-5-5-18 at 1.8V

    By default the ram HAS TO be able to work at 1.8V. It is MANDATORY for every manufacturer. Then the manufacturer can make them better performer either by upping clock, decreasing latencies, or increasing/decreasing voltage accordingly to what was their goal: performance or lower power consumption.

    So either you use:

    clock: 400mhz (800mhz, since DDR means double data rate)
    latencies: 5-5-5-18
    voltage: 1.8V

    clock: 533mhz (1066mhz)
    latencies: 5-5-5-15
    voltage: 2.2V

    There are other settings you can use but the first one is on par with the JEDEC standard, the other one has more punch. Seems like 4-4-4-12 latencies are actually an overclock. Since you can't make the memory sticks to work for now, stay clear of those timings until you get them to work the way they are intended.

    Tom's hardware tested those ram and here are their results when overclocking ram:

    ... Only CL5-5-5-15 timings are supported, at 1.8 V default voltage or at 2.2 V maximum voltage ... We started our overclocking attempts at the default DDR2-1066 voltage of 2.2 V, which didn’t take us much further than the default speed. However, a slight increase to 2.3 V helped to reach DDR2-1130 reliably. Any faster speed would result in the system becoming unstable.

    (possible typo here since in the review Cpu-Z gives us a bit different numbers, being DDR2-1140)

    For the max overclock, they used 5-5-5-18-2T latencies. Here's the review in case you want to give it a look:,2024-5.html

    Also as 4745454b pointed out already, when you overclock by raising FSB clock, make sure the ram does not exceed 570Mhz (1140mhz) at 2.3V maximum. Reduce the ram multiplier so that you get close to the ram's specified speeds with normal voltage accordingly to it's clock. THEN when everything is fine, you can try other settings and clock (don't exceed 2.3V).
  3. I'd like to add 2.3v is a LOT for DDR2. I believe most of the kits I've seen say that if you are going to run higher then 2.2, you MUST use active cooling on the sticks. (its a fan that clips to the ram sockets.) I'm not sure I would use 2.3.
  4. cheers guys

    I'll try them suggestions. Really appreciate the help.
  5. Best answer selected by oakenfolk.
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