DRAM Timing Control

Posted on 2004-11-30
Last Modified: 2008-01-09
I have had this issue before, and I would like to attempt the same solution again, but I need help with the settings.

I worked with a level 3 techie from mushkin, and he helped me determine the proper settings in this part of the BIOS and it fixed my problem. I, however, was never told what the options meant, and thus cannot figure it out for myself. In my opinion, the auto timing for DRAM sucks on most BIOSes, and I prefer if it is manually set.

I will give you the specs, and options in the DRAM Timing Control:

The processor is a Pentium 4 - 2.8ghz
The BIOS is a Pheonix-Award Workstation BIOS
The RAM is one DIMM of 512MB DDR PC3200
The Power Supply is a 420W ATX

The options in the BIOS are as follows:

DRAM Timing Control - (By SPD, Manual)
DRAM CAS Latency - (2T, 2.5T, 3T)
RAS Active Time(tRAS) - (6T, 7T, 5T, 4T, 8T, 9T)
RAS Precharge Time(tRP) - (3T, 2T, 4T, 5T)
RAS to CAS Delay(tRCD) - (3T, 2T, 4T, 5T)
DRAM Addr/Cmd Rate - (Auto, 1T, 2T)

I would appreciate any help in getting the right settings here... if you need more info, please let me know...

Matthew Wadsworth
The Computer Guy
Lancaster, California
Question by:The_Computer_Guy
    LVL 4

    Expert Comment

    Hi Matthew,
    I will not bore you with the exact calculations of what the various settings should be as there are hundreds of
    configurations you can tweak and set up.
    However, simple explanation on one page with the basics of functions for DRAM's in general is what I will offer you :-Þ
    Check out which gives a good overview of the fuctions.
    Normally when you only have one slot with memory you won't really make a massive improvment by changing the CLK or Timing controls, it's more of use when you have memories with different speed.
    Hope this is useful though,
    LVL 7

    Author Comment

    To be honest... my proficiency is not up to par enough to decide from the information you have given me. perhaps if I were given the same information in idot-speak, I would retain more.
    LVL 8

    Expert Comment

    Hi Mathew

    It actually depends of what your memory is capable of. But Lower is best.
    Various programs can read the SPD info from your module.

    Everest has never failed translating SPD values compared to manufacturers spec.

    download Everest home

    Menu Motherboard/SPD shows your memory sticks capability
    MEnu Motherboard/Chipset shows your current setting.

    You can use this to setup your BIOS manually

    LVL 8

    Expert Comment

    Sorry should have been
    Everest has never failed *me*, translating SPD values compared to manufacturers spec.
    LVL 3

    Accepted Solution

    Its not the answer you want, but its not just as simple as one setting suits all.  If you have extremely high quality ram on a great pcb then you end up with a stick that *might* do 2-2-2-5 (cas lat, precharge, delay & active) however if you have less than the best, but still good memory then *maybe* you are looking around a 2.5-3-3-7 using kit from a known manufacturer.  

    Bad makes go even lower, but when I say bad i dont just mean unheard of, theres plenty of good memory companies that only occasionally ship over to the west, the usual ploy for badly manufactured memory is that it'll meet most of the specs, be marketed as 'budget' and be wildly out on one timing, which usually ends up tipping the performance applecart over the harbour wall.

    Also to consider is the faster memory gets, the slower it gets too, ddr2 is coming through on intel chipsets already and that has much higher timings, 2-2-2-5 would never work for ddr2.

    The only way to really satisfy your curiosity is to acually benchmark them.  Sit down with your favourite synthetic memory benchmark, start with very relaxed timings (3-5-5-8) and change one at a time, test it, score it and reboot.  (While you are doing this also note how little the changes actually affect real performance).

    Otherwise, if you want a quick and easy solution, stick 2.5-3-3-7 in and (assuming the ram is reasonable quality and your pc runs ok) leave it at that.  You wont get much better unless you have some very expensive enthusiast branded ram.  If it complains then back off the 3-3 to 4-4 and reboot - if it runs then thats it - tuned and your job is jobbed.
    LVL 3

    Expert Comment

    oh- and if you want peace of mind, run a good memory tester such as memtest86 (free) after the tune, just to satisfy yourself that its not so close to the line that its throwing errors.

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