Overclocking help P5b & Q6700

[Driv3n]

Originally posted by: elconejito
a better cooler will help the CPU, but it won't help your RAM. My Q6600 idles around 30c and maxes at around 50c with a Zalman 9700.

Try lowering your FSB just a few Mhz into the 390s. 390x9 will give you 3.5Ghz... isn't that close enough to 3.6?

Isn't that going to change the memory divider from 1:1 to something else? I wouldn't mind lowering to 3.5GHz, as long as it is stable and can run at 1:1.

Is this even possible?

It may only seem like 400MHz to some people, but I notice a significant speed/performance increase at 3.6GHz 1:1 over 3.2GHz 1:1.


Do you think my problem is really the memory, or is it more the fact that I'm using four 2Gb modules?

Thanks.

 

[elconejito]

It shouldn't change the divider. IIRC, When you set the FSB speed you should see the memory speed right below it. Just make sure it is less than 800.

I agree that a 400Mhz increase in CPU speed (3.2 to 3.6) is noticeable. Not so much if your just surfing the net. But if your running video encodes or filters in photoshop, those few seconds (in some cases minutes) add up. Better overall productivity. If you can do it, go for it. I couldn't get mine much over 3.2 without adding a lot of volts so I settled for 3.2 and was very comfortable with temps, volts, etc.

I know that definitely the 2GB sticks won't let you go over 400mhz FSB. Can the fact that you have 4 sticks affect the overclocking overal, yes. But the real limit right now is the 2GB sticks *.

*I suppose "if" your RAM has the SPD set correctly, and "if" the motherboard chooses the right SPD (hit or miss since you're overclocking) then it is "possible" to get over 400MHz FSB if the RAM timings set automatically.

 

[n7]

Originally posted by: elconejito
Hey there Driv3n. I was running a P5B with a Q6600 and 8GB of RAM up until december. The problem is that the P5B doesn't like 2GB sticks of RAM. If you have a 2GB stick of RAM (doesn't matter how many sticks) you can't run the RAM at over 800Mhz. There is a thread over in the motherboard section called "Official P5B" thread (or something like that) and myself and a couple of others have run into this problem. It's on the last few pages of that thread.

The solution is to either run the RAM at less than 800Mhz (literally, 799Mhz is OK but 800Mhz is not) or use sticks that have less than 2GB. The root of the problem is that there is a timing that needs to be set for the RAM and you can only manually set it to 42 (I think) and it needs to be higher, like 54+ IIRC. Some RAM manufacturers set this correctly in the SPD, but it's hit or miss whether it will work. For me it was just easier to run the RAM at 1:1, and then I eventually just got a new mobo.

Also, if you're stuck at a certain FSB, try going up a little higher. The P5B has lots of "holes" where no matter what voltages you give it, it fails Prime every time. so if 400 isn't working, try 399 or even 401 (or maybe 390/410, you get the idea). I was running my Q6600 at FSB 359 and it was rock solid, and barely had to give it any more voltage.

Hope that helps.

EDIT: It just sank in that you're running your FSB at 400Mhz. Drop it down a few Mhz and keep it running 1:1 and you should be fine.

Not true

The problem isn't really 2 GB DIMMs, it's that the maximum tRFC value one can manually set is 42.
2 GB DIMMs can generally run up to DDR2-800 (though some good ones will do DDR2-1000ish) with the tRFC @ 42.
To consistently reach DDR2-800+ speeds, you will want tRFC at 48-52 or higher for most 2 GB DIMMs.

Now if the RAM's SPD has been programmed with tRFC set to 50+, & you use the auto/SPD settings for the RAM in your P5B Deluxe, you can run well over DDR2-800.

Unfortunately, some RAM manufacturers aren't too bright, & they programmed the tRFC value in SPD to be far too tight, so on a board like the P5B-D where you either must run it AUTO or set it manually, you are basically screwed.

Here's some proof that you can run 8 GB over DDR2-800

4x2 GB mixed Mushkin & G.Skill on my P5B-D @ DDR2-1000
http://ense7en.com/pics/P5B-D/...205-5-5-18%20(SPD).jpg

2x2 GB Mushkin @ DDR2-1100 on my P5B-D
http://ense7en.com/pics/P5B-D/...0DDR2-1101%2083%25.jpg

For me, the trick was letting SPD control the timings, which would set tRFC to 51

I did find that with 3 or 4 DIMMs, i could not get over 400 FSB with my Q6700, but getting the RAM to run a higher speed wasn't an issue as long as i let SPD timings do their own thing.

There's no question that the P5B-D isn't really the best board to be running 2x2 GB or 4x2 GB on, as when it was made, the idea of running 4 GB was crazy high end, nevermind 8 GB.
But considering its age, if you know its quirks, i found it to be a pretty amazing board for its time, not to mention that it's still very useable for high end systems today.

/i still run it with a Celeron E1200 @ 3 GHz & my 2x2 GB G.Skill @ DDR2-938 (tRFC is only 43 btw )
http://ense7en.com/pics/P5B-D/...DR2-938%205-5-5-13.JPG

 

[Rafael]

Another thing you should consider is that when running at some FSB frequencies the NB strap changes automatically (I can't remember now @ what strap it will be running @ 400 Mhz, if it is 266 Mhz or 333 Mhz) and it degrades your performance, so running @ 400 Mhz will give you a better performance than running 405 Mhz (test wirh SuperPI), it is just an example that shows this fact I am saying.
And since you are concerning about the temps and performance.
Also tightening the timings in memory will not help, and if you try to run timings like 3 will perform worse than running timings in 4.
So I would say that staying with FSB @ the most of 400 Mhz (or even lower) and running memory @ 1:1, will be just a matter of the combination of vcore, multiplier to achieve the sweet spot of your desired OC at a reasonable temps.

 

[n7]

Yeah, the strap is changed at 400 or 401, i forget which.
Keep in mind 1:1 automatically applies a rather high tRD, which is another reason to avoid using 1:1 if at all possible on the P5B-D.
4:5 & 2:3 apply tighter tRD, which improves performance.

 

[bruceyg]

Your Vcore is a bit high to me, I am running my Q6600 @3ghz with P5B deluxe board, the VCore I set in the BIOS is 1.225V, super stable under prime95 test.
My board was pencil modded to decrease the VDroop. Before modded, it required 1.25V in Bios to be stable at 3Ghz.

Originally posted by: Driv3n
Would someone tell me which setup would yield overall better performance and speed.

400 FSB 8x mulitplier = 3.2GHz
CPU VCore: 1.4000v
DRAM @ 1:1 w/2.25v

or

320 FSB 10x multiplier = 3.2GHz
CPU Vcore:1.4000v
DRAM @ 2:3 w/2.25v



I only ask because my temps are slightly higher with the 1st setting.

Thanks.

 

[bruceyg]

 

[elconejito]

n7 where you you 6months ago when I needed you?

Originally posted by: n7

Originally posted by: elconejito
Hey there Driv3n. I was running a P5B with a Q6600 and 8GB of RAM up until december. The problem is that the P5B doesn't like 2GB sticks of RAM. If you have a 2GB stick of RAM (doesn't matter how many sticks) you can't run the RAM at over 800Mhz. There is a thread over in the motherboard section called "Official P5B" thread (or something like that) and myself and a couple of others have run into this problem. It's on the last few pages of that thread ... snip...

Not true

The problem isn't really 2 GB DIMMs, it's that the maximum tRFC value one can manually set is 42.
2 GB DIMMs can generally run up to DDR2-800 (though some good ones will do DDR2-1000ish) with the tRFC @ 42.
To consistently reach DDR2-800+ speeds, you will want tRFC at 48-52 or higher for most 2 GB DIMMs.

I thought the problem was limited to 2GB sticks because (I'm paraphrasing here) the density of the sticks required certain timings (like tRFC) to be significantly looser than those for 1GB sticks at a certain speed. So if there was a 1GB stick that required tRFC of >42 then yes it wouldn't work, but I didn't think such a 1GB stick existed.

Is that wrong?

Originally posted by: n7
Now if the RAM's SPD has been programmed with tRFC set to 50+, & you use the auto/SPD settings for the RAM in your P5B Deluxe, you can run well over DDR2-800.

Unfortunately, some RAM manufacturers aren't too bright, & they programmed the tRFC value in SPD to be far too tight, so on a board like the P5B-D where you either must run it AUTO or set it manually, you are basically screwed.

Here's some proof that you can run 8 GB over DDR2-800

4x2 GB mixed Mushkin & G.Skill on my P5B-D @ DDR2-1000
http://ense7en.com/pics/P5B-D/...205-5-5-18%20(SPD).jpg

2x2 GB Mushkin @ DDR2-1100 on my P5B-D
http://ense7en.com/pics/P5B-D/...0DDR2-1101%2083%25.jpg

For me, the trick was letting SPD control the timings, which would set tRFC to 51

There's the rub. I couldn't find definitively which of the 2GB sticks had a tRFC set high enough. There were a couple that "might" work including a muskin, OCZ, and maybe one other (I can't recall which). But I couldn't find out for certain and I didn't want to go through the trial and error of it since this is for my work box. So I just put up with sub-800mhz speeds until I changed motherboards. If I had seen this info before, I would have picked up that set of RAM and kept the P5B.

Originally posted by: n7
I did find that with 3 or 4 DIMMs, i could not get over 400 FSB with my Q6700, but getting the RAM to run a higher speed wasn't an issue as long as i let SPD timings do their own thing.

There's no question that the P5B-D isn't really the best board to be running 2x2 GB or 4x2 GB on, as when it was made, the idea of running 4 GB was crazy high end, nevermind 8 GB.
But considering its age, if you know its quirks, i found it to be a pretty amazing board for its time, not to mention that it's still very useable for high end systems today.

/i still run it with a Celeron E1200 @ 3 GHz & my 2x2 GB G.Skill @ DDR2-938 (tRFC is only 43 btw )
http://ense7en.com/pics/P5B-D/...DR2-938%205-5-5-13.JPG

Agree 100% with the bolded statement. It overclocked like a champ, had a ton of features, was reasonably priced (I definitely got my $$$ worth out of it). It is right now in my parents box, and I suspect it will be there for a long time.

 

[n7]

Originally posted by: elconejito
So if there was a 1GB stick that required tRFC of >42 then yes it wouldn't work, but I didn't think such a 1GB stick existed.

Is that wrong?

There's the rub. I couldn't find definitively which of the 2GB sticks had a tRFC set high enough. There were a couple that "might" work including a muskin, OCZ, and maybe one other (I can't recall which). But I couldn't find out for certain and I didn't want to go through the trial and error of it since this is for my work box. So I just put up with sub-800mhz speeds until I changed motherboards. If I had seen this info before, I would have picked up that set of RAM and kept the P5B.

No, that's correct.
I was just clarifying that the issue isn't really the DIMM size per say, it's tRFC.

On the note of which RAM has a looser tRFC, well, it's something where you can find out by contacting the manufacturer, or by getting users to post screenshots of their RAM's SPD values in MemSet or Everest, etc, as those will show tRFC.

Unfortunaterly, it does seem motherboards seem to ignore the built in SPD values & set their own, as for example, on my Mushkins the P5B-D sets the programmed 51, yet for my G.Skill (which are shown as programmed 51), it does 43

Or maybe the wrong tRFC is being read from SPD...not sure.

 

[elconejito]

Originally posted by: n7
No, that's correct.
I was just clarifying that the issue isn't really the DIMM size per say, it's tRFC.

Oh, OK. Glad I'm not crazy (not that this proves one way or the other ), but I probably should have been a bit more clear in my original post.

Originally posted by: n7
On the note of which RAM has a looser tRFC, well, it's something where you can find out by contacting the manufacturer, or by getting users to post screenshots of their RAM's SPD values in MemSet or Everest, etc, as those will show tRFC.

Unfortunaterly, it does seem motherboards seem to ignore the built in SPD values & set their own, as for example, on my Mushkins the P5B-D sets the programmed 51, yet for my G.Skill (which are shown as programmed 51), it does 43

Or maybe the wrong tRFC is being read from SPD...not sure.

I searched long and hard for "concrete" (or somewhat close to) evidence of a specific RAM that would work, without success. I was specifically looking for people who were running 8GB (or at least more than 4GB) at over 800MHz. There aren't a lot of people running 8GB of RAM, less running 8GB on *this* board, and even less running it at over 800MHZ :laugh:. Based on a lot of googling, and reading through forums (like this one) I came across a couple that might work. I contacted a few manufacturers for confirmation who gave what seemed like a canned response of "it might work, but we can't guarantee compatibility" which essentially left me in the same boat of not being "sure". And like I mentioned I didn't want to go the trial and error route (yes, i'm a bit lazy).

If I had seen your screenshot back then I would have jumped on the Mushkin bandwagon in a heartbeat. Maybe for the OP that set might be a good choice if a) the RAM is definitely what is holding them back, which I suspect it is and b) would rather spend the $$$ on the RAM than a whole new mobo.