An overclocking question

I should start by saying that I am not looking for a big overclock.  I don't want to have to change voltages, and would be happy with a few MHz.  I know this sounds crazy, but I want to do this more as an academic exercise then a risky performance boosting task.

Assumption 1:  It is a good idea to run the CPU FSB in a 1:1 ratio with your memory.

Assumption 2:  The FSB of the processor is quad pumped, and thus for the 1:1 above, my 1333 default is really 333MHz.  (I am rather sure for this one as the 333 times the multiplier of 9 gives the 3.0GHz)

Assumption 3:  DDR2 ram is double pumped as thus my DDR2-800 has a real frequency of 400MHz.

Conclusion:  If I set this at a 1:1 I should be able to keep my DDR2 at default, this would make my FSB of processor be 400MHz, times the multiplier of 9 would give me a 3.6GHz operating frequency.


My problem is that when I go into the bios, and link the frequency of the ram to the CPU at a 1:1, it reads ram frequency of 1333.  My default right now has it at 800.  So this readout seems to be operating frequencies. 

I also discard changes upon exiting because I don't want my misunderstanding to run my ram at almost double the rated speed.

Can someone please help me fix my confusion.

So just to make sure I understand 100%, the bios option of 1:1 matches effective speeds.

But when people recommend that the cpu and ram frequencies match(unpumped)  since the cpu pumps twice as hard, I need a 2:1?

If I'm following you, what you are proposing is not exactly a trivial overclock. Going from 3.0 GHz to 3.6 GHz, if you can do it at all, will probably require a substantial increase in Vcore up to the neighborhood of 4.0 1.4 V. Of course, it depends on how many hours (minutes?) you want your machine to run without errors.

Edited by Bill the Cat - 18 Feb 2008 at 12:06pm

Originally posted by Bill the Cat If I'm following you, what you are proposing is not exactly a trivial overclock. Going from 3.0 GHz to 3.6 GHz, if you can do it at all, will probably require a substantial increase in Vcore up to the neighborhood of 4.0 1.4 V. Of course, it depends on how many hours (minutes?) you want your machine to run without errors.   If it were possible to set Vc = 4 V, it would, of course, mean instant death for the CPU and any other parts on the motherboard that got in the way.

Thank you for your concern.  I perhaps wasn't clear.  I only want to do a trivial over clock for learning purposes.  The 3.0-->3.6 was stating the max over clock assuming sync mode and given my ram is rated at speed DDR2-800.

p.s.  I love that this computer came with a community.

Bill, your sig...

The Vcore...

I've got a VCore of 1.408.  This has been an extremely stable rig since I've gotten it.  I haven't had one BSOD, lock-up or glitch from the time I kicked this thing on.

Well, one thing did happen when I booted it up for the first time.  It drained all the power from my neighbor's houses to boot this nuclear beast.

Originally posted by Bill the Cat Tyler, Thanks for being my editor. I just can't get used to the idea that modern chips run at such ludicrously low voltages and the the difference between life and death for a chip is measured in millivolts. My grip on the present comes and goes.... Advice seekers take note.

It's O.K. Bill, I still find myself slipping up from time to time and saying I have 2Mb of system RAM instead of 2Gb. Something in my head also occasionally rejects the current reality.

Bill,

DSO did the overclock.  As I indicated before, the CPU was liquid chilled and from all the readings I was looking at (CPU-Z, Speedfan) all temps were with normal.   Of course bios had everthing that was over the manufactures suggested limits in red (If I remember vcore, fsb, etc).

Originally posted by EdH63 1.5 and beyond does seem quite high.

There is a pithy aphorism that goes something like:

"Before you try to beat the odds, make sure you can survive the odds beating you."

Edited by Bill the Cat - 22 Feb 2008 at 10:24am

Welcome to the forums Rajeev! Keep up the awesome work in the facility. It's great to see more and more employee's becoming active in our community.

Care to put some lotion on your skin?!!!

No complaints Rajeev. Not from me.

I always assumed DSO was using values from a table or spreadsheet based on worst case  to arrive at an overclock figure for given configurations, and then went back and did some trial and error when settings based on that spreadsheet did not work, or failed the stress testing. I assumed this to be true because it's taken me months of experimenting (and cooling modifications) to arrive at the values my particular CPU will operate best at, and I couldn't imagine DSO techs have even a small portion of that kind of time to get a sytem overclocked and ready to ship.

I could be way off base with that, but I assumed the overclocks that shipped would be considered fine for the vast majority, and would be volted to the point there was zero doubt of stability. My reasoning was this was to minimize the load on customer service since BSOD's  might appear once in a blue moon at lesser voltage levels, and "once in a blue moon" multiplied by thousands of systems is a lot of phone calls.

For those like me that simply love to tweak, the overclock I started out with gave me a basic framework and understanding of how the values worked together. I took the voltage levels as a "maximum" to work within (1.5V was the setting on my B3 stepping Q6600 CPU when I recieved it), and began tuning using online guides from there seeking the sweet spots for my specific chip. So for me, the $25 I paid for an overclock was well, well, worth the price of admission to gain insight on a world I was barely aware of prior to receiving my beautiful machine.

When I suggest a voltage level is a bit high, it's not really a criticism, it's based on my own experience with fine tuning an overclock. Whereas I assume that DSO doesn't have the time to really fine tune each and every system, I also assume the customer has nothing but time with their chip, and if they are here in this forum looking for help with that, it's because they were looking for something different from their overclock, be that faster clocks, or lower temps.

I simply give the best advice I can on how to begin that process, no slights aimed at DSO or it's Techs are intended. If my assumptions were off base, please correct me.

Originally posted by EdH63 Tyler, just once I'd like to see you getting out of that massive brain matter you swim in and post a wildly stupid and funny comment that doesn't make sense at all. Come on baby, I know you can do it!

Originally posted by Bill the Cat Originally posted by Rajeev Any gripes or complaints can be aimed at me. My experience has shown me that 1.5v on an Intel CPU, especially a Quad Core is not an acceptable amount. Rajeev, it's great to have a pro overclocker on the forum. I look forward to your insights. However, in the spirit of the forum, where no mistake is too small to jump on ("Vc = 4V"; big deal!), be careful what you type. I don't think this is what you meant.

As long as he didn't mean... VD.

Thanks for the kind words Rajeev, I still have trouble thinking of myself as "knowledgeable" so much as "learning, and trying to learn more". I'm glad my posts have been received in the spirit they were written, and I have also taken absolutely zero offense. My experience overclocking is limited to a single B3 stepping Q6600 while you've seen hundreds, if not thousands of systems.

Originally posted by Rajeev So I was wondering, can I borrow $20.00?

See, I was going to offer, but I never lend money to friends or family.



Bill and Ed,  my corrections of the 4V figures *is* me being silly. Apparently my sense of humor still needs some fine tuning.

Originally posted by Tyler Lowe Bill and Ed,  my corrections of the 4V figures *is* me being silly. Apparently my sense of humor still needs some fine tuning.