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Is this really as good as it gets?


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OK - Intel 975XBX2 board, E6600 CPU, 2 GB Corsair CM2X1024-6400C4 (2 X 1 GB)..

 

BEST I can get is 2.52 GHz on CPU. That's with 4-4-4-12 timing at 2.12 v @ 800 Mhz on memory.

 

Anything higher on CPU frequency and memtest86+ version 1.70 crashes with memory errors.

 

Can anyone suggest any changes, or do I have bad parts? (Or is that as good as Corsair can do?)

 

(I was expecting MUCH better performance capability!)

 

The Gunny

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Please download CPU-z from Here and post screen shots of your CPU/Memory/SPD tabs after the overclock.. You can use http://www.photobucket.com to upload the graphics.

 

You are NOT overclocking correctly. Drop your DRAM to 667Mhz and raise your FSB. This will concurrently raise your DRAM speed. Use CPU-z and the memory tab (Memory X 2 = Dual Channel) to tell where your DRAM speed is and you should be able to clock higher.

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Thanks, Derek! Tremendous help!

 

It seems counterintuitive to me that slowing down the memory frequency (800 -> 667) would allow faster cpu speed. Seem like that would create a condition whereby cpu was potentially waiting on memory, causing double fetches. While you might get faster CPU speed, overall system would be slowed by empth [potentially] fetches. That discussion is probably best saved for another day... :laughing:

 

Anyway, so now I'm up to 3.00 GHz on the cpu. The screens from CPU-z are:

 

http://i221.photobucket.com/albums/dd233/GunnySpook/cpu-z-SPD.jpg

http://i221.photobucket.com/albums/dd233/GunnySpook/cpu-z-Memory.jpg

http://i221.photobucket.com/albums/dd233/GunnySpook/cpu-z-CPU.jpg

 

Let me know if these don't work. My target was 3.2 (which is somewhat arbitrary, but I just want best 'bang for the buck' without having to go water to cool, or having a highly unstabile (or even moderately unstable) overheating system.

 

Where would you suggest I start pushing to get closer to 3.2? Now it chokes if I try to get past 3.0.

 

Thanks again, Derek. You've been a tremendous help already!

 

The Gunny

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Thanks, Antipacker.

 

I really don't want to have to push or coddle beyond about 3.2 GHz. I just don't want to have to deal with, or work hard to "sort out" my machine.

 

I respect what you've done, but that's just not where I am. I just want to be sure I'm getting the most I can *reasonably* get without extreme effort.

 

Now, I do realize that I'm probably shortening the life of my machine by reaching beyond the design specs, but after all, there's "equipment" life, and then there's "usable" life. I figure my usable life of this cpu-memory combo is about 2 - 2.5 years. I can't imagine that I'm shortening it to anything less than that.

 

The Gunny

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I just don't want to have to deal with, or work hard to "sort out" my machine.

 

I'm going to be a bit tough here, but if you do not want to deal or work hard to sort your machine out, then stop at 3.0. You will need to do some tweaking now to gain stability and that is work. No, you will not need water-cooling but you WILL need to tweak that board a bit.

 

I can't imagine that I'm shortening it to anything less than that.

 

I doubt that you will lose that much. Expect more life than that but in theory, I fully agree.

 

It seems counterintuitive to me that slowing down the memory frequency (800 -> 667) would allow faster cpu speed.

 

No, Firstly, when you lower CPU speed you allow slower CPU speed, when you raise CPU speed you allow faster CPU speed. Lowering and raising the DRAM does not effect the speed of the CPU. It effects the speed of the CPU <--> DRAM throughput.

 

Secondly, if you take a look at your Memory tab in CPU-z you will see that you are at 417.7Mhz with a ratio of 4:5. Now with Dual Channel that is 417.7 X 2 = 835.4Mhz. Your 800MHz DRAM is running 35.4Mhz faster than the 800Mhz spec.

 

Now here's the thing. When you raise your CPU FSB, you concurrently raise your DRAM throughput. It works on a ratio. If you left the DRAM at 800Mhz and raised your CPU FSB from 1066 to 1333 you concurrently raise the DRAM far far higher than 800Mhz. See? Now you can set to a 1:1 Ratio. Set your FSB to 400Mhz. Set your Core Voltage of the CPU to 1.4V, Set your Northbridge MCH +.05v, set your DRAM to 4-4-4-12 and 2.1v and at a 1:1 Ratio. Your CPU is 400Mhz (QDR = 1600Mhz). Your DRAM is 400Mhz (DDR = 800Mhz).

 

Test with memtest before entering Windows. If memtest passes, then enter Windows and test with Prime95. You may need to raise your CPU voltage incrementally to find stability. This is dependent on your CPU. Some do not need it, some do. That's the fun of overclocking, finding just what your parts will do together.

 

NO soldering is necessary :p:

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Derek, unfortunately, in a spasm of cleaning and organization, I pitched the CPU box (and the stock fan it contained).

 

However, I have Everest, and it tells me the CPU is a B2 stepping. Can't help on the lot though. I could probably pin down the date it shipped to me if that would help.

 

VID (from CoreTemp) is 1.25v.

 

And I'm running a Zalman 9500 cooler inside a Lian Li box.

 

The Gunny

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VID (from CoreTemp) is 1.25v.

 

And I'm running a Zalman 9500 cooler inside a Lian Li box.

 

You have a "B" Fab even if you do not have the box. You can find this on your CPU as well. You have a VERY good processor for overclocking. It needs far less voltage so I would drop it down to 1.3 to test with Prime95 and even lower possibly. Keep in mind that this processor runs warmer than the "A" Fab (do not confuse with the B2 Revision). So you need to find stability and the 1.4v is fine but once you find your system stable, then you need to incrementally drop your CPU Core Voltage. 3.2GHz is a cake walk for that processor but they run warmer. My last E6600 was a L629B330 and made 3.6GHz on air easy. So you should have no problem with 3.2Ghz.

 

The date won't help but your VID shows that you have a cherry. No L6xxAxxx fab had a VID that low. Only the L6xxBxxx had and the lowest I have seen on a desktop VID was a 1.225 which was mine.

 

Just keep an eye on the load temps. No higher than 65C on full Prime95 Dual load and at 3.2GHz with ~1.3v you should be under 60C full load.

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hi derekt sorry to use this thread but im at 3.6ghz but need 1.5v check my specs for hardware. i have a b2 e6600 i use a big typhoon my temps it uguru on full load never over 52 degrees

 

Different processors need different voltages. Very likely your processor needs more voltage. I doubt you have a low VID Core 2 and this is why you need more voltage. This is common for the L6xxAxxx fabbed processors which make up the vast majority of Core 2 Duos. If you are at 3.6 stable and full load does not go over 52C then you are doing very well and should be very pleased. Your "A" fabbed processor runs cooler than the "B" fabbed processors by a fair margin and what makes the "B" fab a cherry is that it needs far less voltage, but it gets far hotter which necessitates higher end cooling such as extreme methods. The "B" fabbed processors go higher with less voltage but Air cooling stops them at ~3.6Ghz. Thus the need for more extreme cooling.

 

Check the results:

 

http://www.x2tech.net/pc/weeks.txt

 

See the L6xxBxxx vs the L6xxAxxx and you will see far less voltage needed on the "B" fabbed CPU's. Hard to find though.

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how can i tell if mines a L6xxAxxx

 

Check your box and look for the FPO/Batch number. Dropping the volts without a long test of Prime95 might well render your system instable. You should post your own thread if you intend on continuing hijacking this one. It's really not fair to Gunny.

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Derek, thanks for your guidance on this process.

 

Now, before I actually 'launch', here's what I'm planning to do:

 

1. CPU Voltage Override 1.375 to 1.400 (After stability achieved with Prime95, try to walk down to 1.300 if possible.)

 

2. Host Clock Freq 334 to 400

 

3. MCH/ICH Voltage 1.55 to 1.60

 

4. DRAM timing 4-4-4-12 (unchanged)

 

5. Memory Voltage 2.12 (unchanged)

 

6. Memory Freq 667 to 400

 

Then test first with Memtest (is 1 full pass sufficient?)

 

Then test with Prime95.

 

If stable, try and lower CPU voltage to 1.3.

 

If it is NOT stable, then adjust Host Clock Freq down? Or CPU voltage up? Reasonable upper limit if that is necessary?

 

If this looks right, give me the green light and I'll start the process.

 

Thanks again for your guidance and expertise, Derek!

 

The Gunny

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I'm not all that sure of your board's settings. First set your DRAM to 667 and all the other settings I gave you. Set the timings to 5-5-5-15 for stability. Then post your CPU-z Memory Tab so that I can see what is going on with your system and the 400Mhz FSB and 667Mhz Memory setting.

 

This will forestall the possibility of issues and will isolate the DRAM from the issue.

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Cpu-z Memory page, fsb set at 345/3.10.

 

http://i221.photobucket.com/albums/dd233/GunnySpook/cpu-z-Memory2.jpg

 

No joy - failed Memtest @400/3.60. Successive tries at 377/3.4; 367/3.3; 356/3.2, all failed Memtest v 1.70.

 

Finally worked (passed memtest) at 345/3.10.

 

Other settings on processor page:

 

CPU Voltage Override 1.400

Enhanced Power Slope Enabled

FSB Voltage override 1.275

MCH/ICH Voltage Override 1.600

 

Memory Freq = 667, timings 5-5-5-15, 2.12v.

 

Suggestions?

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Note that in the CPU-z you are running your DRAM at 862Mhz. You need to drop your DRAM speed in the BIOS to increase the FSB of the processor. So, drop to 533Mhz and increase your FSB again. When you find your CPU-z memory at 400Mhz, then you are once again at your DRAM spec.

 

It was my mistake. You need 9 X 357Mhz on the CPU. I don't know the DRAM multipliers on that board but you want to be as close to 800Mhz as you can. You can tell in CPU-z. 400Mhz in the Memory tab in CPU-z means 400 X 2 (Dual Channel). Memtest will also tell you the Dual Channel speed. Stick as close to 800Mhz as you can.

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Derek, dropping the memory freq to 533 helped pass Memtest, but the system was so unstable, I couln't boot into anything to even run cpu-z.

 

So I started dropping FSB, ultimately to 367/3.3, where I got this snapshot of the memory tab.

 

http://i221.photobucket.com/albums/dd233/GunnySpook/cpu-z-Memory3.jpg

 

 

Still too unstable to even get into apps to make a copy of the screenshot though.

 

Right now I'm at 356/3.2, with memory at 533, 5-5-5-15, 2.12v and it seems very unstable...

 

I haven't even tried Prime95 yet.

 

The Gunny

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Ram Guy you'll have to be very specific with me.

 

In this instance, the CPU was running at 3.6 when I reduced memory frequency to 533 as Derek suggested, and I had to gradually reduce it to 3.2 to even get enough stability for Outlook to load and run.

 

So I'm confused by your suggestion to 'overclock' the CPU to gain stability. ??

 

The Gunny

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Derek, dropping the memory freq to 533 helped pass Memtest, but the system was so unstable, I couln't boot into anything to even run cpu-z.

 

Good, you have isolated the DRAM from the issue, now you have only the CPU to work with for stability.

 

So I started dropping FSB. Right now I'm at 356/3.2, with memory at 533, 5-5-5-15, 2.12v and it seems very unstable.

 

Good. Thlis is what you are supposed to do. You were not expected to be stable at the high CPU setting. You were supposed to find enough stability to boot so as to effect dropping FSB.

 

Please also Memtest any changes to DRAM timings and speed before entering Windows. Also test any CPU changes with OCCT for 30 minutes. If stable, then when you are finished tweaking and testing with OCCT, you can move to ~8 hours of Prime95 testing on the small fft's.

 

Use OCCT Perestroika for a quick, hard and fast CPU stability test. Download Here

 

What are your voltages set at with these settings. The DRAM is 2.12 but what are your CPU voltages?

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