1. ## Confused about GA-P35-DS3R Memory FSB

I have a GigaByte GA-P35-DS3R with a Q6600. When I do a 3.0 Ghz overclock, I increase my CPU FSB from 266 to 333. Thats a 67Mhz increase. I thought that increase would carry over to my 667 Mhz memory, adding 67X2=134 to my 667 equaling 801 Mhz. My MB Bios shows the new memory FSB as 833 Mhz. This is verified by CPU-Z. Why the difference in the the 833 vs 801 Mhz?

2. You are running it on the divider. 1:1 will give you 666, 4:5 will give you 833. (2x FSB)/(Divider)= (2x333)/(4/5)=833. You adding does not add up becasue of divider which you should divide. Increase in FSB by 67 (from 266 to 333). (2x67)/(4/5)=167.

3. Does that mean if I have the SPD in the Bios set to Auto, the MB is going to choose a divider that will get the FSB for the memory as close to the memory specification? I am somewhat of a newbe so I don't have a good understanding of memory dividers. I am probably coming off as an idiot, but what would be the divider if I were to overclock 800 Mhz memory. What speed would 800 Mhz memory need to be capable of?

4. There are memories that are underrated, like pc5400 capable of running speeds of pc6400. The best way for you, since you are overclocking memory too, to set divider manually. Also use memtest86 to see if there is no errors at that speed.

5. if you select 2.0 instead of auto for the spd, then your ram will run 1:1

6. Based on the above calculations I can get two different speeds if I calculate a 4/5 divider for overclocking 800 Mhz memory. If I use a 4/5 divider and use the formula (2X467)/(4/5)=1167 or if I use (2X67)/(4/5)=167+800=967. Which would be the correct speed?

7. Originally Posted by ffzen
if you select 2.0 instead of auto for the spd, then your ram will run 1:1
When I look at the bios the next memory setting up from auto is 2.5.

8. Originally Posted by PCSOFTN
Based on the above calculations I can get two different speeds if I calculate a 4/5 divider for overclocking 800 Mhz memory. If I use a 4/5 divider and use the formula (2X467)/(4/5)=1167 or if I use (2X67)/(4/5)=167+800=967. Which would be the correct speed?
(2x467)/(4/5)=1168

The second one is not necessary. It was just to show if you increase fsb by so much, what kind of increase you would get on memory. It relates to your first post when you were adding 134 to 667.

If fsb is 467, then it is increased by 201

(2x201)/(4/5)=502+666=1168

9. Originally Posted by PCSOFTN
When I look at the bios the next memory setting up from auto is 2.5.
It should be further down

10. Originally Posted by meionm
It should be further down

Sorry I missed it? Thank you for your help and putting up with a newbe.

Originally Posted by PCSOFTN
Sorry I missed it? Thank you for your help and putting up with a newbe.
Hi guys,

I'm really noob in overclocking my GA-EP35C-DS3R mobo with Q6600 and 4GB (2x2GB) DDR2-1066 Corsair Dominators (PC2-8500). What I need help on is how to overclock it with the correct settings. This isn't my first time overclocking, but I can't seem to understand or get it right. I was told that the Dominators are better and faster when dropped to 800mhz instead of 1066mhz. I pasted the current settings I have with CPU-z. I just want to know if I have the correct voltage settings on my Ram and CPU to keep the overclock stable. As of right now my timings for the rams are 4-4-4-12 with a ram multiplier of 2.00 (as stated above) and my q6600@3.6ghz with multiplier of x9 and FSB is at 400. As of right now I everything seems stable i haven't seen a jump or change in the core speed...but then i'm not sure if cpu-z froze. Let me know if i have everything set up correctly. I'm not too sure but my FSBDR ratio is 1:1

12. At the current FSB of 400MHz, change the MCH Strap / Latch from 2.00D to 2.66D for an effective 1064MHz DRAM frequency. Also change the four primary RAM timings from 4-4-4-12 to 5-5-5-15-2T, and manually change the DRAM voltage to match what Corsair spec's the RAM to run at. And the only things we can see from the single pic. you posted are the current Vcore, FSB, and multiplier. In order for us to see the current FSB : DRAM ratio, you'll need to post a pic. of CPU-Z open to the 'Memory' tab. Also post a pic. w/ it open to the 'SPD' tab, so we can see what the SPD timings and voltage are at DDR2-1066MHz.

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