FSB Overclocking Results


Front Side Bus Overclocking Testbed
Processor: Intel Core Duo
T2400 -1.83GHz
CPU Voltage: 1.400v (1.250V default)
Memory Settings: 4-4-4-15 at 667MHz
Memory Voltage: 2.15v
NB Voltage: 1.575V
PCI-E Voltage: 1.525V
Cooling: AOpen Supplied Cooler
Power Supply: FPS FX700-GLN
Maximum CPU OverClock: 255fsb x 11 (2805MHz) +54%
Maximum FSB OverClock: 255fsb x 11 (2805MHz) +54%


Click to enlarge

This board is a very good overclocker although it does have a couple of quirks. The BIOS allows you to overclock the front side bus by 1MHz increments but you are limited at both the minimum and maximum levels by a set of jumpers. If the JP4 and JP5 jumpers are enabled the board defaults to a 166MHz minimum and a 199MHz maximum. If these jumpers are disabled the board defaults to a 200MHz minimum and a 320MHz maximum.

The Core Duo processor does not allow a change to the CPU multiplier so keep this in mind when deciding what CPU to purchase. We were able to take our retail CPU to a setting of 11x262 before we hit a ceiling with either the board or the CPU utilizing the stock cooling. We are reporting our maximum numbers at 11x255, not because of the board or CPU not being stable at 11x262, but due to our comparative Opteron 175 only reaching this level and remaining stable. This board series has reached the 274FSB level based upon user experiences, so we either reached the limit of our CPU or possibly our board does not overclock quite as well as retail samples.

Considering the maximum official Core Duo CPU is currently running at 2.16 GHz, an overclock to 2.882 GHz (using the relatively inexpensive T2400 CPU) is nothing to complain about! We might even add that our retail CPU stayed in the 36c to 39c range under load at the overclocked settings with the AOpen supplied heatsink/fan. Additional testing with a watercooling unit brought our temperatures down to the 26c range under full load as we reached a 267FSB level (required 1.675V on the Nortbridge, 5-5-5-15 memory timings) before the board would not post.

Memory Stress Testing



Memory stress tests look at the ability of the AOpen i975xa-YDG to operate at the officially supported memory frequencies of 667MHz DDR2 at the best performing memory timings the Corsair CM2X1024-6400PRO revision 1.4 will support.

AOpen i975Xa- YDG
Stable DDR2-667 Timings - 2 DIMMs
(2/4 slots populated - 1 Dual-Channel Bank)
Clock Speed: 166MHz (667FSB)
Timing Mode: 667MHz - Default
CAS Latency: 3
RAS to CAS Delay: 3
RAS Precharge: 3
RAS Cycle Time: 8
Voltage: 1.9V


The AOpen board was very stable with two (1GB) DDR2 modules in Dual-Channel mode at the settings of 3-3-3-8 at 1.9V. The board would set tRAS to 12 if the memory selection was left on auto. We did not notice any issues throughout our testing with a tRAS setting of 8 at the stock 11x166 setting. We will now install our Corsair modules into all four available memory slots, which results in more strenuous requirements on the memory subsystem than testing just two DDR2 modules.

AOpen i975Xa- YDG
Stable DDR2-667 Timings - 4 DIMMs
(4/4 slots populated - 2 Dual-Channel Banks)
Clock Speed: 166MHz (667FSB)
Timing Mode: 667MHz - Default
CAS Latency: 3
RAS to CAS Delay: 3
RAS Precharge: 3
RAS Cycle Time: 12
Voltage: 1.95V


The AOpen was completely stable with four (1GB) DDR2 modules in Dual-Channel operation at the settings of 3-3-3-12. Note that tRAS had to be changed from 8 to 12 along with a slight memory increase to 1.95V. These are excellent results as the board performed superbly throughout our memory testing regimen that included eight to twenty four hour runs of MemTest86 and Prime95 along with numerous iterations of SuperPI set at 32M. This board along with the Intel 975X core logic is about as solid as it gets.

Board Layout Test Setup
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  • Myrandex - Thursday, May 4, 2006 - link

    Believe it or not, people can run 64bit apps for other reaons from 4GB memory...such as increased performance? I knwo not many apps right now show increased perofrmance with 64bit mode, but some do and I believe this will go up when more developers start programing for it with more intensity and all that.
    Jason
  • peternelson - Thursday, May 4, 2006 - link

    For me this is the showstopper, and the reason I much prefer Turion at present.

    Core Solo/ Core Duo are 32 bit only. That makes them quite rarely disadvantaged - even the new Celerons can do 64 bit EM64T.

    This board would be of much more interest if the review said "THIS BOARD IS MEROM-READY". As it doesn't, I assume it isn't. The review here might have highlighted this important issue which will be crucial deciding factor for some potential purchasers, especially considering the price.

    I see Conroe and Merom systems quickly filling the market need this board is targetted at.
  • Gary Key - Friday, May 5, 2006 - link


    quote:

    Core Solo/ Core Duo are 32 bit only. That makes them quite rarely disadvantaged - even the new Celerons can do 64 bit EM64T.


    Only disadvantaged for those utilizing 64-bit applications and operation systems, but for 95% of the marketplace they are fine. Not that I do not think it is an issue, but one that is way overblown in today's marketplace.
    Probably in a couple of years it will be completely different but for now, 32-bit applications are still king of the hill (market share wise). This upsets me as I have to believe the entire migration path should have been completed by next year but the foot dragging between Microsoft and Intel negated AMD's advantage in this area for far too long. With that said, Merom takes care of the Yonah 64-bit issue in the mobile sector for Intel in a couple of months. It will be very interesting to see how it compares to Turion 64 X2, it will be good for all of us to have choices in the mobile sector.


    quote:

    This board would be of much more interest if the review said "THIS BOARD IS MEROM-READY". As it doesn't, I assume it isn't. The review here might have highlighted this important issue which will be crucial deciding factor for some potential purchasers, especially considering the price.


    We cannot quote on whether this board is Merom approved or not until qualification testing is complete. Will a Merom T7400 work in this board with the bios 1.3b, yes it will, and the initial results show a great deal of improvement over Yonah in certain benchmarks. Will Merom be fully supported by Intel and AOpen on this board, we do not know yet. AOpen is waiting a production spin of Merom before trying to the qualify it on this board and even then Intel might force everyone to Crestline for official support. We are still trying to figure out if Merom is going to work with 945GM as stated a couple of months ago. The entire situation is so up in the air right now that any statement has the potential to be wrong so being quiet is the best possible option. :)
  • johnsonx - Thursday, May 4, 2006 - link

    from the spring idf article on AT:

    quote:

    The other beauty of Merom is that it is 100% compatible with existing Yonah designs, meaning that all Core Duo notebooks today should be able to accept a Merom processor with at most a BIOS update.


    Now that may not be a 100% promise, but until Merom is actually released, there's no way to be 100% certain any given board will work with it.
  • Viditor - Thursday, May 4, 2006 - link

    quote:

    You plan on running apps that require greater than 4GB of ram in the next couple years?

    You mean 4GB or greater...at 4GB, a 32bit processor will be using PAE already.
    And yes, I find that 4GB is a great help on a number of my apps...
  • Questar - Thursday, May 4, 2006 - link

    Mobile/SFF apps?

    Name them.
  • Viditor - Thursday, May 4, 2006 - link

    quote:

    Name them

    Photoshop CS2, Premiere Pro, and Mental Ray...
  • Questar - Thursday, May 4, 2006 - link

    I'm a heavy Premiere user, and I can tell you it's a 32 bit app.
  • Chadder007 - Thursday, May 4, 2006 - link

    You can still run it under a 64 bit OS and have access to the 4gb or greater amount of ram.
  • defter - Thursday, May 4, 2006 - link

    No you can't. If you have an 32bit software then it can only address 4GB of memory.

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