Question about Max Memory Frequency (Mhz)

[nodestar]

Hello.

I've recently started to work on Overclocking my machine. I've done lots of reading and searching but something I can't seem to get my head around is the Max Memory Frequency. And how you find out what that number is.

My Ram is CORSAIR XMS2 2GB 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Desktop Memory Model CM2X2048-6400C5.

According to Easy Tune 6 (I'm not using this to OC. I just have it) the Max Bandwidth is PC2-6400(400Mhz)

I'm not really sure if that means 400Mhz per Ram stick or what.

 

My setup is a Gigabyte MB with a Intel Core Duo E8400 Wolfdale 3.00Ghz.

 

My goal is to OC my system as high as the ram is willing to go at a 1:1 ratio and then stop. I'm ok with the Ram holding the CPU back. I just want to know what the Max Memory Frequency is for my Ram. Because I'm not looking to encounter blue screens or startup errors.

 

Any explanations would be helpful. Thanks for reading.

[CowKing]

Hello.

I've recently started to work on Overclocking my machine. I've done lots of reading and searching but something I can't seem to get my head around is the Max Memory Frequency. And how you find out what that number is.

My Ram is CORSAIR XMS2 2GB 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Desktop Memory Model CM2X2048-6400C5.

According to Easy Tune 6 (I'm not using this to OC. I just have it) the Max Bandwidth is PC2-6400(400Mhz)

I'm not really sure if that means 400Mhz per Ram stick or what.

 

My setup is a Gigabyte MB with a Intel Core Duo E8400 Wolfdale 3.00Ghz.

 

My goal is to OC my system as high as the ram is willing to go at a 1:1 ratio and then stop. I'm ok with the Ram holding the CPU back. I just want to know what the Max Memory Frequency is for my Ram. Because I'm not looking to encounter blue screens or startup errors.

 

Any explanations would be helpful. Thanks for reading.

if you want a 1:1 ratio the highest you can go is 3.6GHz on your CPU(that's if you want to keep the memory at 800MHz). The maximum memory frequency is how ever high it will go.

At any rate, just make sure you have adequate cooling and you should be fine, but an e8400 should easily hit 4GHz and would encourage you to push your machine

[nodestar]

So the Maximum Memory Frequency just goes up until it just won't work any more and thats the stopping point?

 

Do you know what type of ratio I might need in order to reach 4Ghz? I know I'd have to experiment with voltages and what not but do you know something to shoot for from experience?

 

I currently am running at 3.6Ghz and my two core Temps are 61C at max load, 41c idle. I have a Freezer 7 Pro. Right now I'm scratching my head because it claims to go up to 2500 RPMs but I can't get it past 1700. Also I don't think my Case is designed well. I don't have an Air intake Fan. So maybe those temps would reduce if I fixed those two problems.

[CowKing]

So the Maximum Memory Frequency just goes up until it just won't work any more and that's the stopping point?

 

Do you know what type of ratio I might need in order to reach 4Ghz? I know I'd have to experiment with voltages and what not but do you know something to shoot for from experience?

 

I currently am running at 3.6Ghz and my two core Temps are 61C at max load, 41c idle. I have a Freezer 7 Pro. Right now I'm scratching my head because it claims to go up to 2500 RPMs but I can't get it past 1700. Also I don't think my Case is designed well. I don't have an Air intake Fan. So maybe those temps would reduce if I fixed those two problems.

Yes, well you can pump more voltage into it to get a higher frequency, but essentially yes

 

You can still use a 1:1 ratio to get to 4GHz, but your memory will run at 900MHz instead of 800. Since your already at 3.6GHz, I'd say your already good and should just do the trial and error method from here on out(increase the FSB until it becomes unstable, then increase vcore)

 

and an intake fan wouldn't hurt

Edited April 30, 2010 by CowKing

[ebarone]

Why are you fixed on keeping a 1:1, if you dont mind me asking?

 

Also, when you see the number 400MHz, remember how to read that: Thats the base clock speed of the RAM, as determined by the FSB speed (400MHz) multiplied by your RAM divider (1:1, or fractionally 1/1, or.. well, 1). But you have DDR- Double Data Rate- so the *effective* bandwidth of the RAM is twice that, or 800MHz. Its NOT the max speed of the RAM, only the maximum RATED speed of the RAM. It conforms to a standard set by a standardization body called JEDEC for the max speed of DDR2 RAM. Anything higher than 800MHz technically, by JEDEC standards, is overclocked. Hope that cleared some things up for you.

Edited April 30, 2010 by ebarone

[RJR]

You may want to try and lower your CPU multiplier to 6 or 7 and then up the FSB to see if the ram will be able to run at 445-450 for your 4.0 Ghz.

 

You will have to up your Ram voltage, NB voltage and it would be a good idea to set your GTL ref voltages also.

[nodestar]

You may want to try and lower your CPU multiplier to 6 or 7 and then up the FSB to see if the ram will be able to run at 445-450 for your 4.0 Ghz.

 

You will have to up your Ram voltage, NB voltage and it would be a good idea to set your GTL ref voltages also.

 

Are you saying that by lowering my Multiplier and Raising my FRB to achieve the same CPU speed I can also lower my Ram Memory Frequency also? So it's more stable?

Example of what I think your saying

 

FSB = 400

Multiplier = 9

CPU Speed = 3.6Ghz

Memory frequency 1:1 = 800

 

FSB = 600

Multiplier = 6

CPU Speed = 3.6zGhz

Memory Frequency = ??? Lower and more Stable??

 

Also I'm not familiar with NB voltage or GTL Ref Voltages.

 

Why are you fixed on keeping a 1:1, if you dont mind me asking?

 

I heard it was the most stable and "natural" way for your CPU to work with your Ram.

Also I'm not really trying to overclock my Ram.

 

I don't know how it all interconnects but I'm running Windows XP. I've heard that Windows XP only allows 4Gigs of ram.(which I have) And that includes the memory from your video card. So I'm only really getting around 3.5G from my ram right now. So is there any benefit to overclocking it?

 

 

EDIT:

 

I've now pushed my machine to 4.05Ghz. 450x9. I had previously set the Volatage to "Auto". At the advice of a guide I read. Maybe on this site. Can't remember. But the author stated that Auto always overshot. So to go as high as your going to go. Then take it off auto and start backing down the voltage until the system becomes unstable. Then move it up. The advantage was that auto kept your system safe why you were experimenting but because it over shot your voltage it generated unnecessary heat.

 

While I was running the torture test I noticed my voltage was at 1.4v According to Intel the range for my processor is 0.85-1.3625. I'm not sure how far this can be pushed but I'm guessing not to far.

 

I took it off auto and changed it to 1.3625. And left everything else the same. My Core temps initially rose to 62c when I move up to 4Ghz. But now they are running at 57c under full load.

In light of this new information should this be my new cap to shoot for? (Go as high as you can until the lack of voltage makes the system unstable) or will my Ram start to hold me back long before my CPU runs fast enough to need more voltage?

Edited April 30, 2010 by nodestar

[ebarone]

Running your RAM at 1:1 doesnt necessarily mean you'll get the best performance out of it, or that it would be the most stable. It really depends on how deep into your timings you'll be wading when OCing your entire system.... for the most part though, keeping it at 1:1 will limit your performance from your RAM. You can pretty much count on your maximum FSB speed being in the 400MHz range, so keeping it at 1:1 means your RAM will never ever breach 1000MHz... now if you keep your timings super tight then maybe thats not too bad, but you really should test it all out. Try running a bigger divider so the RAM runs faster and see if your system runs faster. Thats the point to OCing right?

[nodestar]

Alright. I haven't learned anything about timings yet. I have mine set to the default 5-5-5-18. I don't really have any idea what they do or how changing them affects the system. I'll look into it.

Also. What is the "bigger divider" your talking about?

 

EDIT: 1 More Question.

 

I have a question regarding the whole Memory Frequency and Ratios thing. Most people talk about the "Latch" or FSB to memory as ratios. i.e. 1:1. My Gigabyte MB doesn't categorize it this way though. Instead in multiplies it. This would be the same in some cases but in most cases it's not. For instance the ratio I've been using is x2.00. This is essentially 1:1 I'm guessing. My FSB is currently at 450. So my Memory frequency is 900.

Now I was under the impression that the other ratio settings like for instance 5:6 made the Memory frequency increase slower then the FSB increase. Essentially holding it back. Because the memory reaches it's limits before the CPU does. So when you get into more advanced ratio settings your always minimizing the Memory increase.

Example

1:1 or x2.00

FSB = 400

Memory = 800

 

5:6

FSB = 400

Memory = 750 (just making these numbers up but my point is that the Memory is lower then 1:1 ratio)

 

Thats my understanding so far. Correct me if I'm way off.

Now if I assume all thats true. And the goal of changing the ratios is to restrict the Memory growth compared to the CPU's growth then my Gigabyte MB multiplying settings are very confusing. Because the options after x2.00 are something like x3.00 and then x4.00. Isn't this the opposite of what I'm trying to accomplish?

Under these settings my FSB would be 400 and my Memory Frequency would be 1200 and 1600 respectively. I thought we were trying to keep the memory as low as possible so the CPU could go further.

 

Anyone have any idea what I'm talking about?

Edited May 1, 2010 by nodestar

[ebarone]

Correct, x2.00 is 1:1, because the memory is DDR2. DDR = Double Data Rate, so at the very least your memory will always run at twice the FSB frequency. But the memory wont necessarily hit its ceiling before your proc does! If you loosen the timings on your memory, its a very good bet to say that your mem can run at 1000MHz, or maybe even 1100MHz. That would correspond to 500MHz and 550MHz on the FSB respectively. 500MHz FSB x9 CPU multi = 4.5GHz, and 550MHz x9=4.95GHz. You probably arent going to get that high on your processor And, well, tbh, you probably wont be able to get your FSB to run that fast either... dont forget that the FSB is its own system, and has its own limitations as well. On my old P35 it was below 500MHz, and I had active northbridge cooling. So you'll probably hit an FSB wall well before a RAM or CPU wall.

 

The suggestion to lower your CPU multi was so that you could find that FSB wall. If your FSB can run at 520MHz, your RAM can probably run at 1040MHz, but your CPU probably CANT go 520*9=4.68GHz. However, if you put your multiplier at 8, you'd get a CPU at 4.16GHz, which is more do-able. Or x7 gets you 3.6GHz which is absolutely attainable. So to find that max FSB, you can run a lower CPU multi and go all out. Doing it that way allows you to know a safe range of FSB numbers, and you can base your overclocking off of that. Its a complex problem so I wont go into too many examples, but try it out and you will absolutely see what I mean.

 

FSB=500

CPU multi =8

CPU Freq = 4GHz

Memory Freq = 1000Mhz

 

Is that better or worse than

 

FSB=450

CPU multi =9

CPU Freq = 4.05GHz

Memory Freq = 900Mhz

 

Well.. thats up to you to find out! It will probably have a lot to do with your memory timings, heat generation, and max stable FSB frequency. So yea... being that theres SO much that goes into it all, you will have to experiment a lot with different settings, and benchmarking them all to see what you can come up with. I hope that cleared a little up for you. Good luck!

[nodestar]

Thanks for the advice. I still haven't touched on Timings yet so I'm going to look into that next.

 

Right now I'm running 450 x9 for 4.05Ghz. I tried going to 480 x 9 I believe and I got errors in the torture test after about 5 seconds. I haven't went through the processes of ruling out whether it was the Ram or CPU. I'm actually pretty happy with my machines speed right now. At least I'm happy with the number 4Ghz compared to the old number of 3Ghz. Even though I don't really see a noticeable difference. I've run the benchmark test using Prime95. I don't understand much of what the results show. Or what it means in application. But I guess it's better. I do want to keep pushing my machine though. Even if it just gets to 4.1Ghz. If for nothing else a learning experience.

 

After a visit to staples and some drill work to my case I've got an Air intake and my Core temps are about 2-4 degree's Celsius lower under max load. As well as the whole system being cooler. Pretty happy about that as it's just one more thing down and out of the way.

 

 

One last note on what I was talking about before with the Ratios. Since 2.0 is the lowest multiplier in my Bios's options then I guess thats the one I'm sticking with. Since I don't want my Memory frequency to be way more then my FSB.

 

EDIT:

 

More about the Ratios thing. I went back into my bios to give this one last look and to make sure I wasn't missing anything. As I've said before I'm using a Gigabyte MB. And that the Bios uses multipliers instead of ratios to change the Memory frequency. But the lowest multiplier is 2.00 which is equivalent to 1:1.

 

Allot of people recommend hitting the ceiling on your FSB, Memory, etc, one at a time. So you know the max for each. Then you bring them together. This doesn't seem possible in my bios because I can't restrict the Memory's increase. The best I can do is use the highest multiplier on my FSB. Which is 9. Which I'm currently using anyway. So right now I'm looking at a situation where theoretically if my Max Memory Frequency was 900. And my Max FSB was 500. Then I could never reach that Max FSB. Because my memory would hold my FSB back. Because unlike with ratio settings, I can't restrict my memory. It's also recommended by some people that once you reach the ceiling on your Memory and your FSB can keep going then to sacrifice memory for FSB. Because "CPU Power is King" This also doesn't seem possible with my bios settings.

 

Surely I'm missing something and this issue has been addressed before. Is there a workaround for this or some other settings that I'm not seeing.

Edited May 1, 2010 by nodestar

[ebarone]

If your max FSB is 500, then your max CPU speed is 4.5GHz... thats probably unattainable. So the only way for your CPU to work in that situation would be to have it at x8, which is 4GHz... you could get that another way though couldnt you? There will always be SOMETHING that will limit your system, be it RAM, CPU, heat, or FSB. How do you know that when you set your FSB to 480 and got instability that it was the FSB's fault? Why wasnt it the CPU's fault? You cant really tell if you leave your multi at 9, and thats why the suggestion was made to lower it for the time being.

 

Why dont you try to find your memory's max stable frequency? That way theres much less guesswork Drop your CPU multiplier to something low, like x6, so you KNOW it will never ever be the cause of instability. Then use a combination of FSB speed increases and creative memory divider selections, and find that max speed. You might be surprised, a lot of people get very fast max speeds from DDR2-800... the 1100MHz range wouldnt surprise me at all. Try 450*2, or 2.4, or 2.5. Theres limitless combinations to try. Good luck and let us know what you get