memory multiplier vs dividers

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fsh42na

[H]ard|Gawd
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Jul 13, 2004
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I'm coming over from AMD to Intel. I know a little bit about overclocking AMD (just enough to get into trouble), but I'm totally confused with Intel overclocking the Gigabyte way. What is the relationship between their "memory multiplier" vs dividers?? I'm getting a serious brain block here trying to picture what is happening here. I've played around with overclocking simply by upping the fsb and keeping my voltages at stock (cept vdimm at +0.2). I had to set "system voltages" to "auto". I'm currently at 3.24 from my stock 2.4. My memory is running about 1080Mhz (if I remember correctly). I'd like to go a little higher, but I think the memory is topping off ( I'd rather not bump up the vdimm much higher). I want to adjust the multiplier/divider, but can't for the life of me figure it out and I don't want any pre-4th fireworks in my house:eek:

Any and all input is appreciated

Thanks

Here's my new toy:

Gigabyte P35 DQ 6
C2D 6600
Ninja B heatsink
2x1gb Gskill PC6400 memory F2-6400PHU2-2GBHZ
EVGA 8800GTS 640 mb
Samsung 500gb SATA x 2 drives (non-raid)
Samsung SATA dvd burner
Corsair 620 w power supply (also have a Thermaltake 850 modular)
Gigabyte Aurora 570 case
onboard sound
 
Same thing, no worries. Gigabyte decided to make is simple and confused the hell out of us till you figure it out.

1:1 is what gigabyte calls 2.0 because on the Intel chipset boards the design was done for the memory to run at 2 x the FSB.

On the gigabytes just multiply the FSB x the memory mulitplier = actual memory speed.

Example FSB = 350 memory multi = 2.5 actual memory speed is 350 x 2.5 = 937.5 MHz

and CPU runs FSB x CPU multi. (which you can reduce from default highest, but not increase)

so simple its confusing :eek:

oh oh there is no divider less than 2.0 it looks like you need to make sure your cpu mulitplier is 9 and memory mulitplier is 2.0 that should get you to 9x400 = 3.6Ghz cpu and your memory will be at stock 2.0 x 400 = 800MHz of course you wont be able to jump right there and if the cpu will not make 3.6 your memory will actually be running under spec speed but cpu MHz are much more powerfull than memroy MHZ, At least it will take the memory out of the mix and you can find your cpu's top end.
 
Bill to the rescue again:D

One question, though. A multiplier of 2.0 is equivalent to 1:1, but my bios (initial release) only has "auto", 2.5, 3.0, etc. Does this mean I can't run 1:1?

Thanks again:)
 
WOW holy undead badgers. I gotta download the manual and have a look at that.

But that is weird.
 
Well, it again looks as if Gigabyte is trying to protect us from ourselves and removed useful options. Auto is per the pre-programed SPD settings in the memory stick. Also missing is the Enhanced Memory option to force the board to use EPP ( extended performance profiles) that can be added to the SPD info by the stick manufacturer in high performance memory.

One can only hope that this is now all automatic and whatever algorithm the bios programmer came up with works.

You can see on the line under the memory divider section what the actual memory speed is, try auto and if after a reboot it is 2 x FSB you are on the 1:1 (2.0x) mulitplier.

I would scream bloody murder at Gigabyte tech support and hope on a new bios release they give back the control to the user. On a performance and high dollar board like yours the user should have the ability to make decisions and have all the flexibility possible. An Auto setting is fine, but the full range of "normal" options should be there as well.

In my book the lack of control over memory dividers is a real negative. Hopefully Auto works well if not I want to know as I dont feel like I could recommend the board with this situation unchanged.
 
fsh42na said:
Bill to the rescue again:D

One question, though. A multiplier of 2.0 is equivalent to 1:1, but my bios (initial release) only has "auto", 2.5, 3.0, etc. Does this mean I can't run 1:1?

Thanks again:)
Click to expand...

well, as Bill said, 1:1 on an Intel chipset would mean 2x the FSB. in order to get the similar type of "1:1" setting, it would mean a multiplier of 2.0.
btw, what gigabyte board do you have? i have the P35-DS3P and whenever i change the multi in the bios, the expected memory speed pops right underneath the multi option (using F4 BIOS)
 
omz said:
well, as Bill said, 1:1 on an Intel chipset would mean 2x the FSB. in order to get the similar type of "1:1" setting, it would mean a multiplier of 2.0.
btw, what gigabyte board do you have? i have the P35-DS3P and whenever i change the multi in the bios, the expected memory speed pops right underneath the multi option (using F4 BIOS)
Click to expand...

I've got their high end P35 board the DQ6. I'm still using their F3 bios that came with the board. I'm gonna reset to defaults and flash to their F4 bios and hopefully there will be a 2.0 (1:1) option for memory multiplier.
 
Good news:) I flashed to F4 bios (not ballsy enough to try the betas yet) and I have 2.0 memory multiplier in my bios now. I haven't installed XP pro yet - just playing with Memtest 1.7 with memory multiplier at 2.0. With my default cpu (E6600) multiplier of 9.0 I can go as high as fsb 370 (running some memtest loops now) for a cpu speed of
3.34 Mhz. However, anything higher I just get reset to stock speeds due to failed overclock. I tried switching my multiplier to 8.0 and upping the fsb, but I couldn't get a combo to work. I initially tried a fsb of 400 to give me 3.2 Mhz (moderate oc) and it just went into a endless loop of reboots that I couldn't stop till I powered down and clear my CMOS. With this 8x multiplier, I then tried fsb ranging from 390 to 350, but I kept getting reset to stock.

I have my vdimm set to +0.2
vcore currently set to 1.375
mch set to +0.05

I can live with a tentative overclock of 3.34, but can't figure out why I can seem to use my 8x multiplier setting.:(

I'm a noob at overclocking and I've heard that you don't install your OS on an overclocked system. On the other hand, if I install my OS at stock and then start overclocking, I run the risk of corrupting my OS, right? What's are your recommendations for me? What are the chances of corrupting my OS shooting for a stable overclock of 3.34?


Thanks for your input and suggestions:D
 
well, I can reach 3.24Ghz with multi of 9 and fsb of 360. If I switch to my multi of 8 and try for an roughly equivalent OC (fsb 400), I can't get there. My puter just try to boot couple of times and then resets itself to stock. All things being equal why would my machine handle 9x360, but not 8x400? I heard and seen that this board/chipset goes upward of 500fsb. Should I bump up my "fsb overvolt" and if so, by how much?

Thanks
 
try 7 x 410 or 7 x 420 to see if it is the MCH/NB strap

The memory controller hub (MCH) gets overclocked just like the cpu when you raise the FSB, internally the MCH will "switch gears" at certain points to allow it to use higher FSBs. Play around with 7X to see what the MCH will do.

Keep an eye on that actual memory speed too, I guess the new bios did not give you the 2.0 mulitplier ?

You can try the FSB voltage, just a little, in the older boards it hurt more than helped, giving the MCH another "tick" of voltage would probally be better.

Here is what the FSB voltage is doing:
http://www.thetechrepository.com/showthread.php?t=87
 
I'm a noob at overclocking and I've heard that you don't install your OS on an overclocked system. On the other hand, if I install my OS at stock and then start overclocking, I run the risk of corrupting my OS, right? What's are your recommendations for me? What are the chances of corrupting my OS shooting for a stable overclock of 3.34?
Click to expand...

Fair to middling :eek:

What I do when playing is to set the boot device to CD or floppy (with no media in the drives or use memtest ) and disable all the other options. Basically I tell the computer boot from floppy or CD or nothing. This allow me to play, reboot, see if the machine will reboot and etc. and I dont chance missing hitting the Del key in time to prevent it from going into windows and crashing. Of course sooner or later you have to reset it and try windows but it helps while trying things out. Booting to memtest is the better way as you can let it run the first test or two just to see if its stable

Another favorite of mine, if other people are NOT using the machine, it to pull the reset switch header off of the motherboard and put it on the cmos reset pins. Then you can reset the cmos by holding in the reset button for 20sec. When all done you can put it back, mine just stays there.

Bios profiles can save a huge amount of time when experimenting, check out the F11 and F12 (i think) while you are in the main bios screen. You loose them on a full cmos clear, but real hand if the machine refuses to reboot and resets to defaults, you can load up you last settings and make a quick correction/adjustment without having to check every setting.
 
BillParrish said:
try 7 x 410 or 7 x 420 to see if it is the MCH/NB strap

The memory controller hub (MCH) gets overclocked just like the cpu when you raise the FSB, internally the MCH will "switch gears" at certain points to allow it to use higher FSBs. Play around with 7X to see what the MCH will do.

Keep an eye on that actual memory speed too, I guess the new bios did not give you the 2.0 mulitplier ?

You can try the FSB voltage, just a little, in the older boards it hurt more than helped, giving the MCH another "tick" of voltage would probally be better.

Here is what the FSB voltage is doing:
http://www.thetechrepository.com/showthread.php?t=87
Click to expand...

Bill

thanks for the info. The new bios actually did give me a mem multi of 2.0 which I was running the better part of yesterday so I was underclocking my memory most of the time.

I'll give your suggestions a try when I get home from work. I could live with my OC (assuming it was stable of course), but it just eats at me when things don't seem to make sense:mad:

Thanks again
 
BillParrish said:
Fair to middling :eek:

What I do when playing is to set the boot device to CD or floppy (with no media in the drives or use memtest ) and disable all the other options. Basically I tell the computer boot from floppy or CD or nothing. This allow me to play, reboot, see if the machine will reboot and etc. and I dont chance missing hitting the Del key in time to prevent it from going into windows and crashing. Of course sooner or later you have to reset it and try windows but it helps while trying things out. Booting to memtest is the better way as you can let it run the first test or two just to see if its stable

Another favorite of mine, if other people are NOT using the machine, it to pull the reset switch header off of the motherboard and put it on the cmos reset pins. Then you can reset the cmos by holding in the reset button for 20sec. When all done you can put it back, mine just stays there.

Bios profiles can save a huge amount of time when experimenting, check out the F11 and F12 (i think) while you are in the main bios screen. You loose them on a full cmos clear, but real hand if the machine refuses to reboot and resets to defaults, you can load up you last settings and make a quick correction/adjustment without having to check every setting.
Click to expand...

Another thanks for that info:D
 
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