Important BIOS Functions

We have picked out a few of the more important BIOS functions for a breakdown of their use and application. The "Advanced Tweaker" BIOS screen has quite a few secondary memory timing options; for the most part these can be left to board/SPD default values. We are providing the best "bang for the buck" manual settings below.

AI Overclock Tuner:
Set this function to manual for overclocking; the Auto function enables preset overclocks automatically when the system is under load.

OC from CPU Level Up:
ASUS enabled overclock profiles based upon the processor type in use; for manual overclocking this function may be left at Auto. If low level automatic preset overclocking is preferred, select either the CPU type or "Crazy" mode. Setting either of the latter two options adjusts all board voltages to preset values. The preset values themselves can be higher than is absolutely necessary for the applied overclock. The Auto overclock functions can be useful for beginners who are getting to grips with overclocking, with the option to move to manual overclocking later. We suppose this guarantees stability via a somewhat brute force approach. For long-term use we recommend using a manually set overclock.

FSB Strap to Northbridge:
The two straps of use for overclocking past 400FSB are 333 and 400. All other straps have lower FSB limits.

PCI-E Frequency:
If the ICH9R SATA ports are used then a setting around 115mhz is safe, though scores do not seem affected by the minimum 15mhz overclock. We noticed anything over 118MHz would cause problems with the drives or even the POST routines. Benchmarkers as usual are best advised to use an IDE drive, turn off all the peripherals, and then try to maximize the bus speed.

DRAM Frequency:
Available dividers are dependent on the FSB strap to Northbridge setting. For 333 we have 1:1, 5:6 and 5:8, while for 400 we have 1:1 and 3:4 memory divider ratios. Best overclocking results and performance are available from the 400 NB setting using the 3:4 divider. Access latency and overall bandwidth seem to reach their peak using the 400 NB strap around 450FSB and upwards with DDR2-1200 memory speed.

DRAM Command Rate:
Sets either 1N or 2N memory timing. 1N has a low memory MHz range (900MHz and under), useful only for the 1:1 divider. 2N is the preferred choice for outright performance when using good DDR2 at speeds greater than 900MHz.

DRAM Timing Control:
Set this to Manual to obtain control of all primary and secondary memory timing ranges. The BIOS shows primary and secondary timings above both respective sections. Users may wish to enter the shown timings manually for each setting and then experiment with tighter timings where possible. The board defaults are generally tight enough for 24/7 use. For benchmarking Memset allows access to setting ranges not accessible in BIOS.

The following three settings are all amalgamated from tRD, tRD Phase adjust, and chipset performance registers areas that are fully unlocked on DFI boards. Rather than direct fine control, ASUS prefers an auto manipulation of preset combinations, with a limited user set range. Results are fairly average using relaxed combinations. The X38 chipset itself seems to favor 333 and 400NB straps, which in turn limits the range of use of ASUS' spin on these settings. We look at possible setting ranges below.

DRAM Static Read Control:
This function is best set to "Disabled" for high FSB levels (450 FSB upwards). "Enabled" gives a small gain in memory access latency at the expense of overall stability. We believe this setting alters a single TRD phase to low; performance advantages either way are not stellar.

AI Clock Twister:
We recommend use of the "Strong" setting wherever possible. Setting "Weak" reduces overall bandwidth and access latency. "Strong" brings the x38 chipset performance almost in line with the P35 using DDR2 memory. Please note, we did not find setting "Weak" worked well with the 400 NB strap at 465FSB.

Transaction Booster:
Ranges here are from 0-7 (0-3 are stated as usable in BIOS), with either the "Enabled" or "Disabled" setting. The 0 setting with either "Enabled" or "Disabled" selects the default tRD level for the NB strap and memory divider combination. The Enabled function lowers tRD (tRD -1) and/or tRD phases with each additional digit over 0, meaning an upward scale increase or boost is more aggressive with Transaction Booster set to Enabled. If using the 333 NB strap, set Transaction Booster to Disabled and use either 0 or 1 as the "Relax level" setting. When using the Relax setting range (Disabled Transaction Booster), using higher numbers will increase tRD (tRD +1) and tRD Phase adjust for lower overall performance, allowing access to higher FSB speeds. For quad-core overclocking the 400 NB strap performs best with Transaction Booster set to Enabled and 0 as the Boost Level setting - unless you're chasing higher FSB speeds at the expense of overall performance. Dual-core CPUs capable of high FSB speeds may use the "Relaxed" setting of 3 if outright FSB speed is the goal.

CPU PLL Voltage:
Scale range is 1.5-3V in 0.02V increments. Stock is 1.5V, although overvolting can bring small increases to FSB limits. We do not recommend using past 1.75V for long-term use.

North Bridge Voltage:
Scale range is 1.25V-1.85v. Stability is greatly affected by NB temperatures, and temps over 47C are prone to failures during longer Prime torture test runs. Active cooling of the NB is recommended for overclocking. A combination of air and water-cooling generates the best results when using the stock ASUS water block and heatsink combo. Voltages around 1.61V-1.65V are required for overclocking past 440FSB.

DRAM Voltage:
ASUS provides us with a searing 1.8V-3.4V scale. The board does overvolt the BIOS setting by around 0.04V, and users are advised to subtract this value from the BIOS setting to stay within warranty voltages for memory ( yes, we said that with a straight face).

Loadline Calibration:
Available options are Auto, Disabled, and Enabled. Use "Enabled" for overclocking. This function reduces Vcore voltage sag. We found a measured droop of around 0.021V under full CPU load and an undervolt of around 0.0125V at CPU idle with the Enabled setting. These are excellent results and ASUS should be commended for addressing previous Vdroop problems on their boards.
Air-Cooled and Subzero Benchmarks GTL Reference Voltages for Quad-Core Processors


View All Comments

  • takumsawsherman - Saturday, November 10, 2007 - link

    Now, we have a close to $300 board, and what we get for that is no Firewire800 support. Amazing. But the sick part is that for $300, you also don't get:

    1. PS/2 mouse. Obviously too expensive to implement.
    2. Poorly attached cooling (a perennial issue dating back at least to A7N8X 2.0)
    3. No parallel or serial, not that anyone would use it. But I'm looking for something they could maybe afford to add when you drop $300 on a motherboard.
    4. Maybe it's just me, but I don't see eSATA, either.

    What a waste of time. Heck, I think the Tyan 1846S/L/A from 1998 had more features, and for $115. At the time, that seemed expensive. Great board, with great support. Now, off to the forums to see what issues the Maximus users are having. I'm betting it's not been all fun and games for them.

    Speaking of fun and games, in 1999, Tyan had a board with a front panel socket surrounding the front panel headers. When I called them, they said they were pushing for a standard interface for that pain in the butt stuff nobody likes to install. One connector. Never happened. Now, Asus should do the same thing. Instead of just moving it out of the case (which is better than the current system, I admit), why not put the connector on the board, and push other mobo manufacturers and case manufacturers to support it.
  • GlassHouse69 - Sunday, November 11, 2007 - link

    yeah. parallel and serial

    they are actually useful if you just dont load up your ipod and play l33t games that pwn.

    no firewire 800 also. it would be like a 50 cent piece of hardware. id say most 2 dollars.

    300 dollars equates to 15 dollars of rediculous cooler that is not needed, 25 dollars at most for the board, and the rest kiddie shit ripoff. People forget the articles 2 years about how much really a "high end" motherboard should cost.

    thanks for playing.
  • LoneWolf15 - Sunday, November 11, 2007 - link

    I couldn't agree more on the PS/2 ports. ASUS' decision to do this on their recent boards has caused me to strike them from my list. I use a KVM to allow me to troubleshoot the systems of others, and PS/2 still works the best for me in this.

    No eSATA ports on the backplate would be forgivable on a board that didn't cost this much, but at near $300, it's ridiculous. Admittedly, eSATA is kind of a future thing, but for the price, you should expect some future proofing. (I checked ASUS' website and found no mention of an eSATA port bracket either, so I'm guessing it's not there)

    I no longer need parallel, though serial is occasionally useful for console-port programming. As for FireWire 800, as much as I'd like to see it adopted, so far it's just not happening on the PC, and I won't fault ASUS for that.

    I think Gigabyte's GA-X38-DQ6 offers a better layout in almost every way except maybe the SATA ports (which is a judgement call - I like the front-port connectors ASUS uses, but they won't work well for every case). And Gigabyte is smart enough to provide both PS/2 ports while still fitting more USB ports, dual FireWire, and all the requisite audio ports. Gigabyte also has a well thought out eSATA port bracket.

    ASUS just loses out on this one. (note: that said, I'll never pay $300 for a mainboard.)
  • Missing Ghost - Saturday, November 10, 2007 - link

    I fully agree with you. 300$ is a lot for a board, for that price you can expect workstation quality. eSATA and serial COM ports are definitely ports that I do use. Also I'm sure the board has tons of problems since it's made by ASUS. Reply
  • Axbattler - Saturday, November 10, 2007 - link

    1. I am not too offended by that. At least it has two more USB ports than Abit's iX38 Quad-GT. That said, Gigabyte can fit both two PS/2 and 8 USB ports in some boards (those without Serial/Parallel ports). It comes down to the connectivity you need - there is a finite amount of space at the back and you will sacrifice something. I'll take two USB ports over one PS/2.

    2. Problematic indeed.

    3. Goes back to point 1. I think it's acceptable for parallel or serial to go. Although optional brackets would've been nice. For the cost though, it is more appropriate in my view to see Firewire 800..

    4. ...and eSATA. What were they thinking? They are basically saying that if you want X38 and eSATA, you have to get a DDR3 boards.

    It looks like while price of Intel CPU today do not have a big mark up compared to AMD at their peak, top end motherboards based on the S775 is a lot more expensive than similarly classed motherboard back then. I remember that Asus's motherboard around the 939 chipset were around £130 back then, somewhat comparable than their top P35 offering today, but well short of most of their x38 - and the MaximusExtreme is close to £200.
  • Raja Gill - Saturday, November 10, 2007 - link

    Some of the points made do show how the makret for extreme products has changed over the last 18 months. For the ROG boards, the users who provide the greatest amount of 'heard' feedback are generally the extreme users. This is probably why the emphasis has shifted away from entry 'workstation level' ports. The ragged edge top end enthusiasts do not seem to mind sacrificing the additional ports for additional board speed, as they would see it at least. Additional peripheral ports do require extra BIOS code and onboard resources (not a great excuse from me, but one of the only ones I can really give). There is of course no justification one can provide in either direction that satisfies both types of users requirements. We can guess that cost and profit margins play a large part in decisions too. What we have seen in recent years is Asus also offerring 'WS' boards that are aimed at overall compatibility and the ports that general PC users deem essential. At this time we have no idea at this time if a WS level variant featuring the X38 chipset is planned.

    regards guys
  • Axbattler - Saturday, November 10, 2007 - link

    Is the ROG series significantly better than the WS series when it comes to board speed/tweaks? Which board (out of any manufacturers) have the best fan monitoring/control of all (and in the event of a tie - which has the best layout/connectivity)? Reply
  • IntelUser2000 - Friday, November 9, 2007 - link

    Boo on the useless expensive products!! Chipsets are the least beneficial in terms of R&D spent. Reply
  • carpediem2u - Friday, November 9, 2007 - link

    I was wondering about this question due to this article.
    Could it be possible to disable of the dual cores in a Quad core CPU?

    Since they are made of two dual core CPU's?
  • Raja Gill - Friday, November 9, 2007 - link

    There is no function in 0505 BIOS to turn off a core or cores, I have not tried the later BIOS releases...


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