Intel D975XBX OC question?

[Boostnjuice]

I need help OCing my rig, I also am using the D 805, and I have an Intel D975XBX Rev 304, 2 gigs Corsair ddr2-667. I have built computers sense the early 90's but this is my first gaming rig. Please don't rant about the hardware, It's what I have and I like it, I runs flawlessly.

now I would like to OC it. I have no unrealistic goals, just as high as I can go and stay stable. My mobo came with a nice stress test software. But the problem is I don't think the BIOS will let me do much, it is updated to the newest version.

Can someone with this mobo give me some tips? and please keep the hatein down.

 

[Boostnjuice]

ok I modified the mobo and unlocked the BIOS, but any thing I change causes it not to POST, it will only run on the default settings?

 

[Vokofpolisiekar]

I'm only using the DCC to push the FSB a bit.

Put generally, the easiest way of OCing a Intel mobo and CPU goes like this (I'm assuming you haven't tried this plus I'm talking in general, not specifically for the 975xbx):

CPU works with multiplier, normally locked except on XE cpu's. Because it's locked, we must then use FSB OCing to raise performance. BUT, seeing that the FSB has a relation to the memory (1:1 / 2:3 / 3:2), one must keep this in mind when increasing the FSB, as the Memory will increase along with this (ie 1:1 means 1mhz up on FSB = 1mhz up on Memory).

With a 800FSB, we have CPU at 200mhz x 4, and this 200mhz will run on the memory (200x2 double data rate) aswell assuming 1:1. But, if you have 800FSB (200), with DDR2 533, then memory is running above the CPU bus at 266.5mhz - 3:2.

Now, if you have 800FSB, and DDR2 533, the easiest would be to set DDR in BIOS to 400mhz. Then, when you increase the FSB to 860 (215x4), the memory will increase at 1:1, and become 430mhz (215x2). This allows you to boost the FSB while still running under the memory's maximum (for DDR2 533 this might be 540mhz max).

You can almost safely push the FSB to 266 (whatever the the multiplier might be - ie 266x16= 4256mhz), and then only will the memory go to it's design speed. Memory timings also play a critical role, so make sure that they are stock standard once locked under their performance - you CAN set tighter timings if the memory is running below it's speed, but you are gradually OC'ing the FSB, so leave it as is for starters.

Please note, this is an example - so don't throw this right away at your setup!!! Use increments of 1-5mhz on the FSB with the DDR locked below it's design speed, test for awhile and look at the temps. If you get to the point where you are running high frequency and Windows dont wanna boot, post again cause then you probably at the limit with default voltages - someone can tell you more than I can about increasing the voltage on CPU in order to get XP to boot if OC'ing.

 

[Boostnjuice]

thanks for the info

 

[dimas]

2Vokofpolisiekar
thanks, that was usefull info to beginners :!:

One quick question though - if I have memory DDR2-800 (I suppose 4x200MHz) and cpu is running on FSB1066 (I suppose 4x266Mhz)
- what would be the OC scenario in this case?
I guess it is 2:3 relation but vice versa. Is it possible to OC in this case?

Thank you in advance

 

[Vokofpolisiekar]

The FSB for 1066 = 266.5mhz.

I haven't worked with DDR2 800, but it should be 800/2 = 400mhz.

So, DDR2 800 will so to speak be at it's peak. You can bump it back to 667 and start working the FSB from there - I don't know how well 1066FSB overclocks though, and how steep the results are with regards to temp and voltages - so take even more care

 

[Boostnjuice]

I finaly got my setup right. I am using Intel's desktop control center, and I am running 3.2ghz solid.

 

[Vokofpolisiekar]

I also played around, and saw that with a normal P4 CPU, one can't really play with mem locking and fsb pushing on the 975xbx. Aparently, there's two point that can be soldered to form a connection, and all options will be available for OC'ing - but I'm not one for custom mods.

The DCC works pretty well, but it works in 1:1 ratio with whatever you have.

 

[Boostnjuice]

I did the OC DBUG mod. I was super easy, I used a Circuit Writer conductive pen, and drew a line from point a to point b.

http://www.xtremesystems.org/forums/showthread.php?t=99298

Pic #3 is the OC DBUG mod, it is right by the BIOS jumper.

 

[Milos]

Is it nessery to do this mod?